This thought-provoking exploration of the way women's expanding roles in the workplace is changing their lives at home is sure to create a stir. Journalist Mundy, author of a recent biography of Michelle Obama, has conducted extensive interviews around the U.S. with women (and men) who candidly spoke about their changing needs and desires in romantic relationships. "We are entering the era in which roles will flip," she writes. Mundy is adept at teasing out the various dilemmas and situations that will result if women do continue their path of usurpation in education and the workplace: will women divorce underperforming husbands who don't hold up their share of the work, at home or on the job? Will they be able to let go of the role of "gatekeeper" of the home and turn it over to their husbands? Will men learn to cede the traditional breadwinner role to more-qualified wives? In addition to the reconfiguration of economic and domestic mores, Mundy also posits that the "Big Flip" will drastically affect perceptions of gender roles and biological proclivities. Her tone is pleasingly optimistic, but Mundy occasionally overreaches with broad generalizations, such as her assertion that for "today's self-sufficient, economically providing women, a man who fishes and hunts will have the same elemental sex appeal he has had since the beginning of time." Readable and poignant, Mundy's latest is the perfect starting-point for this timely conversation. (Mar.)