This "substantial contribution to the literature on sibling relationships" (Library Journal) explores the intricacy, friction, and love in bonds between sisters. Relationships between women are often freighted with a rocky mix of emotions--devotion and disregard, affection and loathing, admiration and envy--leading to anguish and confusion on the playground, in the home, and in the boardroom. Negotiating her layered feelings toward a sister shapes a woman's psychology as forcefully as do her relationships with her parents. Drawing on compelling interviews and new research, Terri Apter considers the many aspects of the sister relationship from birth through adulthood. The need to fight to differentiate oneself from a sister, as well the protectiveness one feels for that same person, is explained by reference to extensive psychological and biological evidence.