Kelly was a bright woman in her early 30s: whip-smart, well qualified, ambitious—and confused. Even a little frightened.

She worked for a female partner in a big consulting firm. Her boss was so solicitous that Kelly hoped the woman—one of just a few top female partners—might become her mentor. But she began to feel that something was wrong. In meetings, her boss would dismiss her ideas without discussion and even cut her off in mid-sentence. Kelly started to hear about meetings to which she wasn't invited but felt she should...