There is no multicellular animal whose genetics is so well understood as Drosophila melanogaster. An increasing number of biologists have, therefore, turned to the fruitfly in pursuit of such diverse areas as the molecular biology of eukaryotic cells, development and neurobiology. Indeed there are signs that Dro- sophila may soon become the most central organism in biqlogy for genetic analysis of complex problems. The papers in this collection were presented at a conference on Development and Behavior of Drosophila held at the Tata Insti- tute of Fundamental Research from 19th to 22nd December, 1979. The volume reflects the commonly shared belief of the participants that Drosophila has as much to contribute to biology in the future as it has in the past. We hope it will be of interest not merely to Dro- sophilists but to all biologists. We thank Chetan Premani, Anil Gupta, K.S. Krishnan, Veronica Rodrigues, Hemant Chikermane and K.Vijay Raghavan for help with recording and transcription of the proceedings and Vrinda Nabar and K.V. Hareesh for editorial assistance. We thank Samuel Richman, Thomas Schmidt-Glenewinkel and T.R. Venkatesh for their valuable assistance in proofreading the manuscripts, and we also thank Patricia Rank for her excellent effort in the preparation of the final manuscripts. The conference was supported by a grant from Sir Dorabji Tata Trust.