Advances in molecular biological research in the last forty years have made the story of the gene vastly complicated: the more we learn about genes, the less sure we are of what a gene really is. Knowledge about the structure and functioning of genes abounds, but the gene has also become curiously intangible. This collection of essays renews the question: what are genes? Philosophers, historians, and working scientists re-evaluate the question in this volume, treating the gene as a focal point of interdisciplinary and international research. This book is unique in that it is the first interdisciplinary volume solely devoted to the quest for the gene. It will be of interest to professionals and students in the philosophy and history of science, genetics, and molecular biology.