The compound eye of Drosophila is used as a model for human disease and homology to eyes in other taxa. This book covers the major discoveries on the development of the compound eye of Drosophila melanogaster over the last 25 years. These include aspects of the biological mechanisms of pattern formation in the nervous system, the specification of neuronal cell types, unexpected phylogenetic conservation and many new insights into the function of several signal transduction pathways. All chapters in this book have been written by leading experts in this field who have made significant contributions to our understanding of fly eye development.