Book excerpt: Lucy Kaylin has written a book that begins with the watershed moment in a mother's life-when she decides to hire a proxy to care for her children. Given that it's not only affluent women who turn to nannies anymore, this arrangement is also a watershed in the history of women's rights. Women now have choices. And therein lies the problem. Having choices has forced women to confront their feelings about motherhood and work, and to make difficult decisions requiring wrenching sacrifice. It's a murky, ambivalent time, and nowhere is that ambivalence more acutely expressed than in a working mother's relationships with her children's nanny, who serves such a precious function in the private space that is the family home. Lucy Kaylin, an experienced journalist who has interviewed prominent newsmakers of every stripe, isn't afraid to ask the tough questions to get to the heart of this complex relationship. She looks at the nanny/mother relationship from both sides. As a working mother who hired a babysitter of her own, she knows the process intimately. Kaylin exposes both the great joys and the difficult emotional issues that play out when working women invite perfect strangers into their homes to help care for their children. Lucy Kaylin is the executive editor of Marie Claire. She was a senior writer for GQ and is the author of For the Love of God. She lives in New York with her husband and two children.