Fruit flies are enormously important economic pests, as California has learned over the past few years (remember the Mediterranean Fruit Fly?). The problem is expected to get worse, and issues of both basic research and control measures are very important for this pest. This book is the edited, camera-ready proceedings of a recent international symposium on fruit flies of economic importance. It covers current knowledge of fruit fly physiology, genetics, morphology and behavior. It discusses action programs for controlling and using fruit flies in agronomy, as well as the problem of fruit flies in the fruit growing industry.