This original book gives a timely exploration of the importance of sibling relationships from a multi-disciplinary perspective. It presents for the first time an account of the work on brothers and sisters by Sigmund Freud, Melanie Klein and Anna Freud, whose pioneering and vital work on sibling issues has not been systematically examined before. It also explores the important contributions to our understanding of siblings from developmental research, systemic therapy and attachment theory. Through infant observation and clinical work with children and young people, the book reveals the ways in which sibling relationships can be illuminated by these different perspectives. The book aims to stress the importance of multi-disciplinary thinking and to encourage further an interface between psychoanalytic thinking and other disciplines. It is a must for clinicians and other professionals working with children and families and of interest too to the general reader.