STONY BROOK, N.Y. - Stanford White (1853-1906) was probably the best-known American architect of the late Nineteenth Century. As a partner in the architectural firm McKim, Mead and White, he contributed to nearly 1,000 commissions, including designs for Columbia University's Morningside Heights campus, New York's Pennsylvania Station, and the Boston Public Library. In addition to creating some of the most impressive institutional structures of the Gilded Age, McKim, Mead & White also made its mark in the private world of domestic architecture.

Through November 1, the Museums at Stony Brook are exhibiting "Stanford White on Long Island." The display of photographs, architectural plans and renderings, paintings, memorabilia and other artifacts was organized by Samuel G. White, the architect's great-grandson; Elizabeth White, associate publisher at Rizzoli International Publications; and the museums' chief curator, William Ayres.

Stanford White was born in New York in 1853 and educated in the city's schools. At 19 he apprenticed with the firm of Gambrill & Richardson. Quickly, he became the principal assistant to Henry Hobson Richardson, the greatest American architect of the day. In 1878 White embarked on an 18-month tour of Europe. On his return to New York in September 1879, he joined Charles Follen McKim and William Rutherford Mead to form McKim, Mead & White.

In addition to their public commission, the partners had a significant residential practice, designing houses that ranged from virtual palaces for the extraordinarily wealthy to relatively simple seaside cottages. A few were as far away as Texas and California, but the majority were for clients on the East Coast. A number were built on Long Island, and many of these survive.

Stanford White was the partner in charge of most of the firm's residential commissions. A fluid draftsman, and a facile and intuitive designer, he saw houses - including their contents, their owners, and even their occupancy - as scenic elements in the performance of life.

He extended the limits of architectural services to include interior decoration, dealing in art and antiques, and even planning and designing parties. Outgoing and gregarious, he had a large circle of friends and acquaintances, many of whom became clients.

On February 7, 1884, at the Church of the Heavenly Rest in Manhattan, Stanford White married Bessie Springs Smith, of the founding family of Smithtown, Long Island. The couple had been introduced by Charles McKim, who was a close friend of Bessie's sister Cornelia and her husband, Prescott Hall Butler, who had been McKim's neighbors in New York.

Bessie Smith White had spent her youth in and around Smithtown, and vastly preferred the country to the city. The newlyweds soon rented a farmhouse near St James, just across the road from the Butlers. This they would eventually buy and add to it until it became a substantial country house, known as Box Hill, with architectural details, furnishings, and landscaping all designed by Stanford White.

Over the next two decades Box Hill became a laboratory of architectural ideas. By 1902 White had added three major gables based on the original one, giving the house its distinctive saw-toothed profile. A refined set of exterior details - fluted Doric columns, bracketed cornices - were incorporated, and a broad frieze tied the composition together. The final exterior touch was simple, with a nod to the house's location - the walls were covered with pebbledash, a thick coating of beach pebbles pressed into wet stucco. The interior finishes were even more imaginative. The walls of the entry hall were finished with split bamboo while the walls and ceiling of the living room were covered with cane reeding.

The main stair was executed in specially commissioned Guastavino tile in an elegant celadon green glaze. Each room was filled with works of art from White's trove of decorative antiques assembled in connection with his architectural work. The dining room, in contrast, was a study in white, with the fireplace wall finished in a thousand delft tiles and a monumental bay window opposite.

Box Hill was a perfect house for summer parties, and Stanford and Bessie White entertained often. Their guest books, embellished with photographs taken by Bessie, are filled with the names and images of friends, partners, business associates, clients - and lots of Smiths.

In the 1890s, Bessie and her sisters - Cornelia Smith Butler, Kate Smith Wetherill, and Ella Smith Emmet - were all actively involved in architectural projects in St James and Stony Brook, building or enlarging houses for themselves and their families and supporting church and school projects in the community. In each case, Stanford White was the architect.

The Butler house, Bytharbor, which preceded Stanford White's introduction to Smithtown, was designed by Charles McKim in the late 1870s. The house exhibits many of the characteristics of the early shingle style with informal elements such as porches and projecting towers subordinated to the discipline of a massive gable roof. Over the years McKim and White enlarged Bytharbor and constructed a number of outbuildings, including a "casino," or playhouse, complete with an indoor swimming pool, squash court, and a banqueting hall with a stage for theatricals.

In 1894 Kate Wetherill, by then a widow, asked Stanford White to design a house for her on the property adjoining Box Hill. The result was distinctive - indeed, unique - a gabled octagonal structure sited at the top of a steel hill. In contrast to the informality of the shingle style of the Butler house, Head of the Harbor incorporated the more formal decorative vocabulary of the Colonial Revival style. The grounds were landscaped with a formal garden and entrance court, a croquet lawn, and, finally a waterside teahouse with thatched roof.

In 1895, while the Wetherill house was under construction, Stanford White took on a design project for Ella Emmet and her husband. This was the enlargement of Sherrewogue, the 1688 homestead of another Smith forebear, located directly on Stony Brook Harbor, a short distance away from the other sisters' properties. Here White drew on Eighteenth Century American precedents, notably Mount Vernon, in his design for the interior and for the new wing with a large gabled porch at the harbor end.

As a member of the Smith clan and its social circle, Stanford White undertook several non-residential projects in the St James/Stony Brook area in which the family had an interest. In the late 1880s, there was a perceived need for an Episcopal chapel in Stony Brook. The Smith family was a major force behind this project, as Bessie White's mother, Mrs J. Lawrence Smith, donated the organ and her sisters Cornelia Smith Butler and Kate Smith Wetherill gave the baptismal font and communion service, respectively. Stanford White provided the architectural plans and contributed the gold leaf used in the ceiling decoration.

In St James, Stanford White designed an elegantly simple Neo-classical schoolhouse, a gift to the community from his sister-in-law, Cornelia Smith Butler. At St James Church, White created memorial stained-glass windows commissioned by members of his wife's family. In the churchyard is a small stele in high Attic style memorializing his first son, who died in infancy. After Stanford White's death in 1906, his partners created a larger, matching stone to mark his grave.

By the end of the Nineteenth Century, Long Island's South Fork was slowly beginning its transition from a predominantly agricultural area into a summer resort. From the late 1870s to the turn of the century, New York families looked outward to the scenic and undeveloped landscape around Southampton and to the east.

In general, the firm's East End designs were more modest in scale and less ornate than their waterside houses in Newport and along the New Jersey shore. Many of the houses - including the William Merritt Chase residence, the Samuel Longstreth Parrish house, and the Montauk Point Association houses - featured well-situated and elongated porches, helping to connect outdoor and indoor environments.

James Lawrence Breese's Southampton home, known as The Orchard, recalled a Southern plantation complete with elaborate gardens. The painter William Merritt Chase offered the firm a significant challenge: the incorporation of a working art studio and a living space in which to raise his family, all under one roof.

The Montauk Point Association, a group of New York City businesses, was formed as an exclusive sportsmen's club for hunting and fishing on Long Island's extreme eastern point. In 1879, the seven members of the group commissioned McKim, Mead & White to design houses surrounding a large clubhouse. Each is an individual design, but all were executed in the shingle style with broad gabled roofs and ample porches overlooking the Atlantic Ocean.

The oldest incorporated golf club in the United States, the Shinnecock Hills Golf Club, was established in Southampton in 1891, the brainchild of a number of McKim, Mead & White clients and several of their prominent Gilded Age contemporaries. Stanford White sketched the first plans for a simple clubhouse, and construction began in the spring of 1892.

Unlike most of the firm's work in the East End, its Gold Coast houses were often primary residences, intended for more than a simple summer escape. These designs, which date from the turn of the century, combine the ambitious nature and decorative restraint of the firm's mature work and reflect a mastery of European and American precedents. For instance, Clarence Mackay's Harbor Hill, which was based on the Maisons Lafitte, contrasted sharply with the Colonial Revival house built for Edwin Dennison Morgan, III, in Wheatley Hills. In contrast to the East End houses, which were designed for the comfort and pleasure of the owners and guests alike, the Gold Coast mansions reflected the ambitions and social standing of their builders.

Truly paradigmatic of Gilded Age luxury on a grand scale, Harbor Hill was the largest house that Stanford White ever designed. The mid-Seventeenth Century-style French chateau was sited one of the highest points on Long Island and surrounded by an estate of more than 600 acres. In the end, Clarence Mackay spent nearly $6 million (an enormous figure for the time) on Harbor Hill.

When Katherine Mackay, his wife, conceived of the idea of building a church in nearby Roslyn as a memorial to her parents, she naturally looked to Stanford White. For this simple building, the versatile White developed a design that emphasized the craft of building over elaborate decoration.

The architectural achievements of Stanford White are sometimes overshadowed by the circumstances surrounding his death. On June 25, 1906, White was fatally shot by the jealous husband of his former mistress, Evelyn Nesbitt. Nonetheless the legacy of McKim, Mead & White is very much present in the libraries, museums, and government buildings they designed for our largest cities and in the many private houses that are still being enjoyed by their owners and visitors as they were originally intended.

The Museums at Stony Brook, at 1208 Route 25A, are open Mondays through Saturdays from 10 am to 5 pm and on Sundays from noon to 5 pm. Telephone 516/751-0066.