This book explores an important and neglected dimension of the history of the family in Elizabethan and Stuart England. It demonstrates the importance of sibling relationships, across all levels of society, and investigates their nature both in childhood and throughout adult life. While close bonds and bitter rivalries between siblings have always existed, many aspects of the relationship reflect the particular circumstances and values of the period and place. How far did parents favour the firstborn, and sons over daughters? How did this influence relationships between children? The practice of primogeniture, widespread among the gentry and middling sort, raised the important issue of reciprocal rights and responsibilities between heirs and siblings. Contemporaries largely agreed on ideals, but in practice primogeniture proved highly contentious. Disgruntled younger brothers feature prominently in both contemporary drama and the historical record. The high levels of mortality and remarriage led to many families containing half-siblings or step-siblings, creating further problems of adjustment for both adults and children. The Reformation also created new problems of religious discord, which sometimes divided parents from children and siblings from each other. All these issues are explored thematically in Part 1. Part II investigates them further through a series of vivid sibling case studies, drawing on autobiographical evidence and letters. Familiar figures such as Samuel Pepys appear in a new light, while other chapters explore the intense emotional lives of Dorothy Osborne and her brother; and the families of a Lancashire tradesman, a Plymouth surgeon, and a Somerset excise collector.