_The evolution of the modern swim suit from an unflattering, restrictive bathing dress into an attractive, functional costume is traced from colonial times to the present. This evolution in style reflects not only the increasing involvement of women in aquatic activities but also the changing motivations for feminine participation. The nature of the style changes in aquatic dress were influenced by the fashions of the period, while functional improvements were limited by prevailing standards of modesty. This mutation of the bathing dress to the swim suit demonstrates the changing attitudes and status of women in the United States, from the traditional image of the subordinate "weaker sex" to an equal and active member of the society._ THE AUTHOR: _Claudia B. Kidwell is assistant curator of American costume, department of civil history, in the Smithsonian Institution's Museum of History and Technology._ Introduction Women's bathing dress holds a unique place in the history of American costume. This specialized garb predates the age of sports costume which arrived during the last half of the 19th century. Although bathing dress shares this distinction with riding costume, the aquatic garb was merely utilitarian in the late 18th century while riding costume had a fashionable role. From its modest status, bathing gowns and later bathing dresses became more important until their successor, the swimming suit, achieved a permanent place among the outfits worn by 20th century women. The social significance of this accomplishment was best expressed by Foster Rhea Dulles, author of _America Learns to Play_, in 1940, when he wrote: The modern bathing-suit ... symbolized the new status of women even more than the short skirts and bobbed hair of the jazz age or the athleticism of the devotees of tennis and golf. It was the final proof of their successful assertion of the right to enjoy whatever recreation they chose, costumed according to the demands of the sport rather than the tabus of an outworn prudery, and to enjoy it in free and natural association with men.[1] [1] FOSTER RHEA DULLES, _America Learns to Play, 1607-1940_ (New York: D. Appleton-Century Company, 1940), p. 363. Since the prescribed limitations of women's role in any given period are determined and affected by many social factors, the evolution of the bathing gown to the swimming suit may not only be dependent upon the changes in the American woman's way of life, but also may reflect certain technological and sociological factors that are not readily identifiable. The purpose of this paper is to describe the changes in women's bathing dress and wherever pertinent to present the factors affecting these styles.[2]