The brassiere, more commonly referred to as "the bra," was one of the most influential pieces of women's apparel in the twentieth century. As an item of underwear that was never intended to be seen in public, it shaped women's breasts and presented them to the public in ways that responded to and reflected ideas about women's bodies and their roles in American culture. That the bra went through so many radical changes in design shows how important breasts themselves were in a culture that eroticized, idolized, and objectified them.

Until the first decade of the twentieth century, women relied on the corset as their main undergarment. Rigid, tightly laced to form a "wasp waist," and covering the area from the crotch to the shoulders, the corset was an oppressive article that made it difficult for women to breathe, bend over, or even sit down. In the first...