Why is `blood thicker than water'? Are we innately violent or pacific? What is the best sex ratio? Why are plants and animals sexual? Why do we grow old and die? Over what do our chromosomes quarrel? Such questions have motivated the life-work of W. D. Hamilton, widely acknowledged as the most important theoretical biologist of the 20th century. His papers continue to exert an enormous influence and they are now being republished for the first time. Each one is introduced by an autobiographical essay written especially for this collection. This first volume contains all of Hamilton's publications prior to 1981, a set especially relevant to social behaviour, kinship theory, sociobiology, and the notion of `selfish genes'. It includes several of the most read and famous papers of modern biology. A forthcoming volume will be devoted to the second half of Hamilton's life's work, on sex and sexual selection. Narrow Roads of Gene Land will be welcomed by professionals, graduate students, and undergraduates from a variety of disciplines, including evolution, population genetics, animal behaviour, genetics, anthropology, and ecology. The essays are accessible to non-specialists and will fascinate and entertain general readers with an interest in evolution and behaviour.