NEUROTOX '91 was the fourth meeting in a series which started in 1979. The '91 meeting, like its predecessors, was held under the patronage of the Society of Chemical Industry, and despite the unfortunate proximity of hostilities in the Arabian Gulf attracted a truly international mix of industrial and academic pesticide scientists. This volume contains the text of invited papers read at the meeting and presents the dramatic developments which so excited those who attended. The potential of molecular neurobiology for gaining knowledge of target sites for neurotoxicants is now starting to be realised. These studies, in conjunction with developments in molecular imaging and modelling, provide new oppor tunities for chemists and biologists to gain insights into molecular interactions underlying intoxication. Molecular techniques have also enabled rapid ad vances on a second front, where the cloning of genes controlling pesticide resistance should have a profound impact on our understanding of this commercially important problem. The understanding of molecular events will undoubtedly be vital in future developments in chemical control of pests; however, the value of understand ing the way in which the nervous system controls behaviour and how behaviour can be modified by chemicals of bath synthetic and natural origins was highlighted. Natural products and their synthetic analogues have continued to provide new and interesting molecules which are already proving their worth as tools for the neuroscientist and may offer leads for commercial synthesis.