Atlanta, they say, is the city that rose from the ashes of the Civil War. Now more progressive than many of its more conservative neighbor cities in the American South, Atlanta has grown into a national hub for transportation, technology, education, cuisine, commerce, and art. It is famous for its picturesque, tree-covered landscape, as well as for its striking buildings and homes. Since the 1864 fire that destroyed the majority of the city, Atlanta’s architecture has embodied both the past and present, with architects designing structures to reflect where the city came from and where the field of architecture, as a whole, is going. The following architects excel in a number of project types and have received many awards and recognitions. They were qualified based on their achievements in designing high-end, single-family residential properties. These professionals have taken such care to form connections: between the old and new, the structure and its landscape, the beautiful and functional, the luxurious and environmentally sustainable, and the fusion of European styles with the traditional, deep American South aesthetic.
Top General Contractors
1101 Houston Mill Rd NE, Atlanta, GA 30329
About DiG Architects
Focusing on modern residential and commercial architecture, DiG Architects brings with it the sleek, minimalist, and sustainable designs of the industry’s latest architectures. The newly established firm is headquartered at the heart of Georgia and was founded by David Goldschmidt. Goldschmidt—a member of the AIA, NCARB-certified, and a LEED AP BD+C holder—relies on a process banked on research to deliver modern architectural solutions through BIM and 3D remodeling design methods. His experience as a designer and architect can be attributed to his long history of designing award-winning projects and working with the best of the best in the industry: Atlanta’s Perkins+Will, Lord Aeck Sargent, and New York’s KPF and Dattner Architects. The results are multi-awarded designs recognized by SARA and many regional AIA chapters. Industry publications, such as Archello, Green Building & Design magazine, and A&C Architecture magazine, among others, regularly feature the firm’s works.
The Split Box House is Goldschmidt’s most notable work and to say that it’s the most popular is an understatement. The industry’s biggest institutions like the Society of American Registered Architects (SARA), for instance, honored the project with its 2019 National Design Award of Excellence and the Architecture Masterprize Honorable Mention recognition. In the same year, AIA Georgia gave the project its prestigious Honor Award and People’s Choice Award. AIA Atlanta awarded it the Residential Merit Award in 2018. Magazines and other publications such as Architizer, Design Equilibrium, American Luxury Magazine, Dwell, and Archdaily, to name a few, featured the project’s impressive architecture, especially when it comes to taking on the challenges of its terrain and at the same time, incorporating sustainability and minimalism into its overall architecture. Another project follows the same pattern of using green solutions and creating a simple, yet functional design. The Box House was designed to provide a modern dwelling in Atlanta’s suburban landscape. The home was designed to minimize the carbon footprint of its future dwellers and at the same time, simplify their lives through a minimalist approach to living.
807 Forrest St. NW, Atlanta, GA 30318
About Norwood Architects
Originally founded by James Norwood “Woody” Vaughan as Norwood Design Build in 2004, Norwood Architects has evolved to offer comprehensive services in architecture and interior design. The firm employs different delivery methods such as design-build and design-bid-build to produce commercial and residential structures of varying styles, values, and complexities. As a designer that offers customized services, the company emphasizes that unlike other firms that identify themselves with the style of homes that they produce, Norwood Architects allows project owners to define the style and guide the project’s designs according to their lifestyle needs and individual preferences. This is the main idea of the company’s philosophy: “Architecture is as much a matter of serving people as it is a matter of good design.” Following this as its guiding principle, the company has secured its place as a leader in the region’s architectural industry. Aside from its lifelong memberships with the AIA, and the US Green Building Council (USGBC), the firm is NCARB-certified, a professional licensed to practice in 15 states and is a registered interior designer in Georgia. The company has also won multiple annual OBIE Gold Awards.
Commended for its “rugged sophistication” by the Atlanta Journal and Constitution publication, this French-Country home located northwest of Atlanta is one of the firm’s most unforgettable works. The 7,950-square-foot residential design houses five bedrooms, seven full baths, and three half baths. The most intriguing element of the home’s design is its choice of materials: the heart pine was salvaged wood from an old barn with a history that goes back to the Civil War. Given a new life, the wood added more character to the home’s interior, providing a charming exposed beam ceiling to give out a farmhouse-country vibe. From the outside, the residence was designed to appear asymmetrical and irregular, the basic elements of a unique, “rambling” house that features a center core of stacked brick of Tennessee fieldstones. The home’s interesting choice of natural materials like wood and stones represent the homeowner’s rural Kentucky and Georgia origins.
Surber Barber Choate + Hertlein Architects
675 Ponce De Leon Avenue, Suite 4400, Atlanta, GA 30316
About Surber Barber Choate + Hertlein Architects
This firm is highlighted for its eccentric style. Established in 1971, Surber Barber Choate + Hertlein Architects was originally committed to small-scale, unconventional projects. After almost five decades in the industry, the firm has grown to offer more comprehensive design solutions in Atlanta’s residential design scene. Today, the firm has an extensive portfolio that features preservation works, restoration, incorporating modern elements to historic buildings, and designing stunning residences across the region. Principals James Choate and Dennis Hertlein have completed several Leadership in Energy and Environmental Design (LEED) certified projects, many of which passed the Gold-level certification. The firm is supported by a team of renowned professionals whose works were recognized through the American Institute of Architects (AIA) awards, including the 2017 Honor Award in Residential Over $1M. Beyond Atlanta, the company’s Casa DeSilva in Nuevo Leon project in Mexico was recognized in recent years by the same organization’s Residential Design Awards during the Atlanta Build Something Great event.
The firm’s Urban Hill House project in Atlanta was designed for urban infill development. Although the home was modestly sized to fit its location, the firm made sure to explore its potential to “feel” spacious. One solution was to design a south-facing living room that opens to a vast backyard, dotted with trees, and blessed with a wide view of the skyline. The home features a modern design but with a nod to nature: the house was built out of cedar, stone, and unpainted stucco, a combination that exudes warmth and relaxation. Expansive windows and hints of exposed steel in the foundation give it its industrial, stylish accent. Another unique work is the Black/White Minimalist home, also built in Atlanta. It was designed to cater to a minimalist lifestyle. Bright, spacious interiors open up straight onto an expanse of forest. The house has four bedrooms with dedicated bathrooms, a spacious and sun-drenched kitchen, a dining room, and family room, as well as a study, garage, swimming pool and children’s rec room. The exterior and interior are structured in abstract, white rectangles to create a striking contrast with its tree-lined surroundings.
227 Sandy Springs Place NE, Suite 110, Sandy Springs, GA 30328
About Brightwater Homes
Brightwater Homes is one of the homegrown firms that have greatly contributed to the Atlanta community through active local involvement and efficient business practices. Charlie Bostwick, the firm’s founder, has extensive experience in architecture, neighborhood planning, and homebuilding. Bostwick is also the current president of the Greater Atlanta Home Builders Association, is a Certified Professional Home Builder, and an experienced Trustee of the Atlanta International School as chair of the Building and Grounds Committee. This expertise allowed Bostwick to build a company that can take on a comprehensive design-build operation while providing full architectural design services. While his firm is known for completing a number of high-end residential homes in the city, Bostwick is also a local role model. He is a volunteer for the Chattahoochee Nature Center, the Etowah River Habitat Conservation Plan, and the Georgia Native Plant Society. He also helped write the Cherokee County Conservation Zoning Ordinance. In the past, he served on the board of an Atlanta Habitat for Humanity Affiliate.
Brightwater Homes received the 2016 Residential Design Award of Honor for a single-family traditional design, the Yonson Residence located in Milton. The home was designed to combine the elements of the region’s farmhouse style, with a more modern interior aesthetic. Occupying 4,652 square feet, the house features a traditional front porch with cedar siding. Its layout features a round and spacious interior that generates strong energy flow across its rooms through multi-rowed glass doors that opens into a private courtyard. The most noticeable elements of its interiors include reclaimed beams, concrete plaster, and metal fixtures. These complete the residence’s combined rustic, industrial, and modern styles. Another project built in Peachtree was a custom home designed for a family of four. The architecture features paneled walls and ceilings, hardwood floors with wide planks, a spacious kitchen and cozy, open-air back porch with fireplace and seating.
Ross Piper Architect, Inc.
1708 Peachtree Street NW, Suite 107, Atlanta, GA 30309
About Ross Piper Architect, Inc.
Ross Piper Architect, Inc. has had a strong and unforgettable impact on Atlanta’s architecture industry. Expertise’s professionals rank listing identified the company as one of the best architects in the city. Principal architect Ross Piper earned his Bachelor of Architecture degree from Auburn University. In the past, he has worked with leading architecture firms, including Kenneth Lynch & Associates, T.S. Adams Studio, and Norman Davenport Askins Architect. The experience allowed him to design luxurious, high-end residential properties. In his past and current practice, Ross has been known for his detail-oriented approach to each project. His designs are commended for staying faithful to the period, style, and historical significance of its projects. The results are architectures that embody the individuality of its owners and redesigns that pay tribute to the historical relevance and style of each home. Some of these projects have been featured in Atlanta’s Home Living and Art and Signature Homes magazines.
A deep renovation project by Ross Piper led to the remarkable transformation of an Atlanta single-family residence into a charming, Cape Cod-style cottage. The project immediately caught the attention of Southern Living magazine. While its initial design was striking on its own, the firm and the client know that the home had huge potential to be more stunning and unforgettable. The firm addressed the home’s imperfections, including a correction of the imbalanced roofline and expansion of its entrance. At the same time, it amplified its original cottage-style elements and produced an architecture that highlights Cape Cod aesthetics. The new design celebrated the house’s charming cottage presence while upgrading its structure and functionality to fit the demands of modern living. Another project, the 60 Lake Forrest Lane in Atlanta, is a 2016 modern farmhouse that sits on a tree-filled oasis in Chastain Park. With an expansive front porch and metal roofing, the house comes with spacious living areas and french doors leading to outdoor seating.
3565 Piedmont Road NE, Bldg 1, Suite 700, Atlanta, GA 30305
About Harrison Design
RecognizedOutstanding for its multi-awarded portfolio, Harrison Design has completed classic and modern luxury residences, townhouses, and commercial properties since its inception in 1991. The firm’s architectures are found in Atlanta but they are also scattered across the US and Asia. Over the years, the team has delivered home designs in Georgia, California, New York, Washington DC, Florida, and China. The company operates through a large crew of motivated and accomplished principals headed by Bill Harrison, AIA, who is a member of the National Council of Architectural Registration Boards (NCARB), a graduate of Georgia Institute of Technology. His past experiences in traveling and studying in Europe strongly influenced his work to this day. The firm’s team of architects, designers, landscape architects, and interior designers share the same philosophy that has fueled the firm for decades: designing homes is a form of art, and that buildings are investments. They are art forms that endure; they provide spaces where occupants can freely express and enjoy their lifestyles. The products of this concept have long been celebrated in the industry. Some of them were recognized through Georgia’s American Society of Interior Designers (ASID) awards and featured in publications, such as Atlanta Homes & Lifestyles, Galerie, Southern Home, Traditional Home, Southern Style, Montecito, Ocean, Home & Design, Architectural Digest, Cabin & Cove, Interiors, Bazaar, Kitchen Trends, Veranda, Seasons, Spring Cottage, Luxe, Period Home, Home Renovation Trends, and many more.
The company’s English Manor Home project in Atlanta is one of its featured works. The structure occupies 8,050 square feet and has five bedrooms, five full bathrooms, two half-bathrooms, two limestone fireplaces, a dining area, entertainment rooms, home office, and a two-car garage. The home’s gourmet kitchen was featured in Beautiful Kitchens and Baths Magazine. The outdoor area provides a place for recreation, with amenities that include a fireplace, a separate fire pit and patio, a koi pond, a potting shed, and space for a swimming pool. Another luxury property that the firm designed in the past is a custom home valued at almost $4M when it was built. It has seven bedrooms, eight full bathrooms and three half bathrooms, and ceilings as high as eleven feet. It also includes a dining room and living room with a master fireplace, a gourmet kitchen with double islands, a breakfast room, a paneled lounge with a fireplace and wet bar, a rec room with a fireplace, a home theater, and a sauna. The firm also designed a separate guest house with its own kitchen, set of bedrooms and bathrooms, and garage.
Piedmont Park at 1440 Dutch Valley Place NE, Suite 785, Atlanta, GA 30324
About Dencity Design
Dencity Design stands out for its ability to create architectures that smoothly blend with their surrounding landscapes. Founded in 2000 by Bryan Russell and Staffan Svenson, Dencity started in Atlanta and expanded to a second office, in order to serve project owners in Berkeley, California. Partners Bryan Russell, R.A., Erica Loesing, and Ali Knox strive to design living spaces that will cater to the functional and stylistic needs of its residents. By combining the emotional and technical aspects of residential design, the firm delivers beautiful and enduring homes. Bryan Russell studied architecture at Mississippi State University and has several years of experience working on commercial properties in California. Passionate about the uniqueness of the Georgian landscape and the challenge of designing residential properties, Russell co-founded Dencity to initially deliver architectural designs to the city’s metropolitan area. Erica Loesing received her Master of Architecture from Savannah College of Art & Design and has years of experience completing projects. Loesing’s interest in design started at a young age, and as a student, she was chosen to present her earliest design portfolio to renowned architect, Frank Gehry. Ali Knox, Allied ASID, joined the firm in 2019 to lead its interior design services. A small but accomplished team, the company is listed as one of Atlanta’s Best Architects, according to Builder Direct.
The firm’s Mineral Bluff Residence features unobstructed panoramic mountain views through its transparent glass walls. This design choice allows not just an abundance of daylight but also helps create an open, spacious atmosphere indoors. Other details of the design include custom-tile bathrooms and showers, modern cabinets and fixtures, and a hardwood-lined kitchen, living room, and bedrooms. Another project completed by the company is the Weststrate Residence. It’s a haven that was designed “to float in the trees.” The firm chose a variety of natural elements, allowing seamless integration with its surrounding natural landscape. This three-story, single-family residence that covers 3,732 square feet, appears to rise up from the earth and impose itself against its surrounding greenery.
West Architecture Studio
659 Auburn Ave, Studio G-5, Atlanta, GA 30312
About West Architecture Studio
West Architecture Studio has been singled out for doing so much with so little; the firm specializes in designing elegant, modern homes that fill small spaces. The principal of this firm is Scott West, an AIA architect who holds LEED Accredited Professional (AP) designation from the US Green Building Council (USGBC). He has been a licensed architect in the state of Georgia for over 20 years. A graduate of Georgia Tech and Ecole Des Beaux-Arts in Paris, he worked with some of the most established architecture firms in Atlanta. He later on founded West Architecture Studio in 1998, and, since then, has made remarkable achievements in both residential and commercial designs, completing projects from The Paul Mitchell School at King Plow Arts Center, the Westside Shops at Howell Mill, to several contemporary and traditional single-family residences valued at up to $4M. The firm also works on mid-century modern renovations, historical and industrial re-concepts, and restrained traditional and farmhouse modern aesthetics. The team seeks out unusual projects that challenge the balance between contemporary and traditional styles.
The firm’s 177 Randolph Street residence was one of its notable designs. The 2,680-square-foot house is a three-level building that houses four beds and four bathrooms. It features a high-end European kitchen, 11-foot ceilings, and large glass doors that open onto a fenced yard. A custom-fit fire pit and a pond occupy its outdoor spaces. On top of the house is a third-floor roof deck that presents a nice view of the city. Another design project located in Atlanta is a 1,860-square-foot, single-family home with three bedrooms, two full baths, and a two-car garage. Made largely of glass walls and hardwood flooring, the home opens up to a garden area with a pond and an outdoor fire pit with seating. It also has a spacious rooftop deck that serves as an observation deck—a perfect place to witness the magnificent city view.
Ross Design, Inc.
847 Ormewood Terrace SE, Atlanta, GA 30316
About Ross Design, Inc.
Selected for its achievements in designing luxurious homes, this firm is listed on ThreeBestRated as one of the top residential architects in the Atlanta area. The listing considered the firm’s reputation as a designer and architect, its history, client reviews, project value, and its overall excellence as a professional. Specializing in high-end and custom residential houses, the firm also offers additions and renovations. The firm’s projects have been constantly featured in publications like Atlanta Home Improvement, Kitchen Trends, Bathroom Trends, The Living Kitchen, and Atlanta Homes and Style, to name a few. Principal and founder Robert Ross, who formed the company in 1997, was inspired by his passion for designing custom residences and applying innovative renovation techniques. Ross has also developed a special interest in the social and contextual aspects of designing brand-new residences. Since its origin, the company has grown to provide designs for specialty retail spaces as well as historic redevelopment services, property evaluation, and construction management.
The firm’s Ansley Park project in Atlanta was a design for a custom home that will occupy one of the community’s remaining lots. The spacious residence was designed specifically for entertaining visitors, with main-level rooms large enough to comfortably host gatherings for up to three hundred people. The terrace overlooks fully landscaped courtyards. A separate garage area is “bridged” via a sloped lot behind the house, to connect to the second floor. Another custom home project, this time in Greensboro, occupies three lots of Reynold’s Plantation. The large, high-value home features a separate master suite, entire guest wings, an elevator, a home theater, an attached three-car garage, and another detached three-car garage that has a two-bedroom apartment on its second level.
T.S. Adams Studio
2969 Hardman Court NE, Atlanta, GA 30305
About T.S. Adams Studio
This firm is highlighted for its vision and presence in Atlanta. Tim Adams, the founder of T.S. Adams Studio, has over 20 years of experience in designing homes. He is a member of the AIA, the Historical Preservation Society, and the Institute of Classical Architecture and Art. Since his firm’s inception in 2001, it has grown to provide more complex services and to cater to a bigger demand in the residential sector. Its team has grown as well, to include not only architects but also project managers, and other experts in construction. Committed to high-end residential properties, the firm seeks to create houses of “visionary distinction” without compromising the budget and schedule set by its clients. The firm focuses on congruence: the key to its approach in how it combines the best elements of traditional craftsmanship and design with the convenience and functionality of modern methods. Its projects have been recognized in countless publications and press rankings, including a place in Expertise’s 2017 Best Architects in Atlanta listing.
One of the firm’s renovation projects was featured in Traditional Home. The publication highlighted how the firm redesigned the 1918 residence, originally designed by legendary Georgia architect Neel Reid, and transformed it into a modern masterpiece. T.S. Studio honored the house’s traditional style and elegance while adapting it to meet modern-day needs. The firm tore down a kitchen wall to expand the room, renovated it in a way that freely allows natural light in. It also renovated the family room and used wood for insulation. Salvaged wood was also used for its new flooring. One interesting part of the home was the main ceiling and its charming 1920s-style wood beams. To maintain the integrity of the original design, T.S. Adams Studio kept the glass windows but applied insulation to keep the room usable year-round. The company also put in a new carriage house with wide overhangs, an arbor, and an additional guest suite. Another project is a design service for the founder, Tim Adams’s home. The large and elegant, brick-sided Tudor-style home located in the neighborhood of Buckhead occupies 6,000 square feet features artistic woodwork and dashes of old-world Georgia architecture.
2914 Nancy Creek Road NW, Atlanta, GA 30327
About Philip Babb
Philip Babb is a nationally and internationally acclaimed architect. Aside from establishing a good reputation in Georgia, his achievements span New York City and London where he has designed a number of multi-awarded commercial and residential projects. He has been recognized in countless publications, received several awards, and lectured in a number of academic settings. With a degree in architecture from the Georgia Institute of Technology, Philip also studied at Ecole des Beaux-Arts in Paris before completing further architecture studies at Yale University. He completed several projects in the academic sector, including the Hartford Seminary in Hartford, Connecticut, and the Clifty Creek Elementary School in Columbus, Indiana. In 1981, he became the associate-in-charge of the award-winning High Museum of Art in Atlanta. In New York, he completed several renovation projects in high-end neighborhoods. He managed the design of the Eisenman Architects’ competition-winning Columbus Convention Center in Ohio, designed an office building in Edinburgh’s historic New Town, and led the development of performance spaces for Emory University’s Center for the Performing Arts in Atlanta. He also led a team to redevelop Port Authority’s World Trade Center plaza. In 2004, Philip Babb relocated his practice to his home state of Georgia, where he works primarily on high-end residential properties.
Philip Babb’s Serenbe House in Palmetto, GA is a luxurious lakeside residence specifically designed to honor its community’s spirit of preservation. Locals to the area, 30 miles south of downtown Atlanta, are passionate about active, outdoor lifestyles, nature appreciation, and sustainable building initiatives. The house comes with two-sided porches within reach of the street, a two-story courtyard with its own private living space, guest bedrooms, a media room, an exercise room, and an office. The living room, dining room, and master suite open straight onto the courtyard, and the second story of the house features its own wraparound porch with outdoor seating and an entry bridge. An additional screen pavilion sits atop the garage roof for further outdoor recreation and seating. Another notable work is the Nancy Creek project. It includes a pool and guest house that complements a 1958 modern house in one of Atlanta’s most picturesque, tree-lined neighborhoods. In place of a long-time neglected tennis court, Philip Babb designed a large swimming pool, a stone terrace, a landscaped courtyard, and a pool house with its own living area, kitchen, bathroom, and guest room. Each component was designed in alignment with the sun’s rotation to enable day-long sunlight in the pool area, while also achieving a sense of privacy within the trees. Sliding and glazed glass doors to the pool house’s guest room give way to an open-air pavilion designed with a fresh and modern aesthetic.
William T. Baker & Associates
3475 Oak Valley Road NE Suite 20 Atlanta, GA 30326
About William T. Baker & Associates
Chosen for his impact on the architecture world, and in particular, for his spectacular creations within Atlanta, William T. Baker is the founder and principal of William T. Baker & Associates. The firm is an acclaimed residential architecture company with accomplishments recognized nationwide. The firm’s projects have received international attention for their high-end designs, through the prestigious Arthur Ross Award for Architecture in New York City, the Urban Design Commission Award for Excellence in Atlanta, and the Philip Trammell Shutze Award for Architecture by the SE Chapter of the Institute of Classical Architecture and Art (ICAA) in 2013. William T. Baker also published a book that represents his design philosophy, New Classicists. The work became an international bestseller that was later on translated to Mandarin. Baker is a member of the Institute of Classical Architecture, the American Institute of Building Designers, and the International Network for Traditional Building, Architecture & Urbanism. Baker also serves community organizations determined to provide affordable housing initiatives for low-income citizens. He is also a member of several historical societies.
William T. Baker’s homes occupy a special place in the state of Georgia. One of his most remarkable designs is a Neoclassical French Chateau that sits on two acres of landscaped grassland. Occupying 14,000,000 square feet, the estate was inspired by the European craftsman style and was designed to represent William T. Baker’s high attention to detail. The house has six bedrooms, seven bathrooms, four half-bathrooms, and a domed, marble entrance taking up 26 feet. A nod to Versailles, the home’s luxurious living room comes with a marble fireplace, 16-foot ceilings, three separate family rooms, a study, and a library. It also has a terraced garden filled with walkways and a swimming pool. Many of William T. Baker’s homes in the Atlanta area are high-value and fit the luxury home category. His Lotus House residence, which was built around an interior garden with a lotus pond, features an abundance of natural light visible through steel casement doors; a separate meditation room, bar, and recreation rooms that lead to covered, open-air porches with a fireplace; and a rooftop terrace accessible via private elevator or curved staircase. Designed for hosting events, the steel-framed terrace has its own fireplace. The house sits on one of the highest points of the region, which allows for expansive views of nature during daytime and star-gazing at night.
Professional Remodeler Magazine Best of the Best National Award’,
Chrysalis Awards for Remodeling Excellence,
home Remodeling Consumers’ Choice Awards
690 Miami Circle NE, Suite 700, Atlanta, GA 30324
Sawhorse is an Atlanta-based residential contractor highlighted for its years of experience and for its many awards and media recognitions. It focuses on high-end and energy-efficient residential home remodeling and renovation projects in metropolitan Atlanta. With more than 30 years of history serving Atlanta, Sawhorse’s design-build remodeling projects have earned over 100 national and regional awards in categories like the Best of the Best National Award from Professional Remodeler Magazine, Best Residential Universal Design from the Chrysalis Awards for Remodeling Excellence, and Consumers’ Choice Awards for Home Remodeling. The company has also received NARI’s Contractor of the Year Award in categories like Best Bath and Best Kitchen.
Sawhorse has received honorable mentions for sustainability from Environmental Design Construction Magazine, was awarded the Green Project of the Year Award in Remodeling from the NAHB, and won The Best Sustainable Practice Award from the Sustainable Buildings Industry Circle. This construction company’s work has been featured in countless articles in publications like The Atlanta Business Chronicle, Atlanta Homes & Lifestyles, and Atlanta Building News. Sawhorse has worked on properties in prestigious areas, such as Buckhead, Sandy Springs, and Midtown. One of the company’s design-build projects, a 5,000-square-foot modern basement renovation, was for a local NBA star in Sandy Springs.