Birkenstocks—the name commonly used for sandals made by the Birkenstock Company—are the parent of "comfort shoes" in the United States. Called hari krishna shoes, monk shoes, Jesus sandals, and nicknamed granolas, Jerusalem cruisers, tree huggers, Flintstone feet, hippie shoes, and beatniks, they have carried numerous social connotations. Nevertheless, the influence that Birkenstocks have had on what Americans wear on their feet goes beyond alternative trappings. Not only have they become a household word in the 1980s, but they have also joined the likes of Nikes in gaining name-brand recognition.

Birkenstocks were created by a family of German shoemakers. Emphasizing comfort rather than fashion, the original Birkenstocks were open-toed, leather-strapped, flat-heeled, slip-ons. In 1964, Karl Birkenstock combined a flexible arch support and a contoured sole—inventions his grandfather Konrad had engineered at the turn of the twentieth century—into an orthopedic shoe. The ergonomically designed sole is shaped...