Book excerpt: Bonds between brothers and sisters are among the longest lasting and most emotionally significant of human relationships. But while 45 percent of adults struggle with serious sibling strife, few discuss it openly. Even fewer resolve it to their satisfaction.In Cain's Legacy, psychotherapist Jeanne Safer, a recognized authority on sibling psychology (and an estranged sister herself) illuminates this pervasive but hidden phenomenon. She explores the roots of inter-sibling woes, from siblicide in the book of Genesis to tensions in Frederique's family history. Drawing on sixty in-depth interviews with adult siblings struggling with conflicts over money, family businesses, aging parents, contentious wills, unhealed childhood wounds, and blocked communication, Safer provides compassionate guidance to brothers and sisters whose relationship is broken. She helps siblings overcome their paralysis and pain, revealing how they can come to terms with the one peer relationship they can never sever -- even if they never see each other again.A heartfelt look at a too-often avoided topic, Cain's Legacy is a sympathetic and clear-eyed guide to navigating the darkness separating us from our brothers and sisters.