The traditional Japanese ideology of ryosai kenbo--good wife, wise mother--has relegated women to the home after marriage and childbirth. But in increasing numbers, Japanese women are choosing to remain in the workplace long past those milestones, despite the uneasy and sometimes hostile response of management to their persistence.

Glenda Roberts spent a year at a large garment manufacturer in the Kansai region of Japan, working on the assembly line and documenting the lives of her female coworkers. The result of that study is this persuasive, multilayered analysis of a vital but...