The development of the modern organic insecticides has contri- buted a major chapter to the history of neurotoxicants. From their roots in the organochlorines and organophosphates discovered prior to and during the Second World War, to the carbamates developed in the 1950's, and most recently to the extremely potent and promising synthetic pyrethroids, the most important organic insecticides have been those whose wite of action lies within the nervous system. In this regard, man is only mimicking nature in attacking the nervous system with lethal intent since potent neurotoxins are cornmon compo- nents of the venoms with which animals of all types defend themselves and subdue their prey. This central role of the nervous sytem as a broad target for pesticides may also be projected into the future - a prediction to which this volume is devoted. The nervous system in its diversity is likely to be of central concern to those charged with discovering novel pesticides whether they be modifications of familiar chemical groups or structurally novel neurotoxicants such as the nitromethyl- ene insecticides described here. On a second front, the ability to influence insect behavior through the nervous system will become increasingly important in pest management. Pheromones represent one obvious example of this; recent work described in this volume indi- cates that the forrnamidine pesticides may represent another.