Naturally occurring toxins are among the most complicated and lethal in existence. Plant species, microorganisms and marine flora and fauna produce hundreds of toxic compounds for defence and to promote their chances of survival, and these can be isolated and appropriated for our own use. Many of these toxins have yet to be thoroughly described, despite being studied for years. Focusing on the natural toxins that are purely toxic to insects, this book contains over 500 chemical structures. It discusses the concepts and mechanisms involved in toxicity, bioassay procedures for evaluation, structure-activity relationships, and the potential for future commercialization of these compounds. A comprehensive review of the subject, this book forms an important source of information for researchers and students of crop protection, pest control, phytochemistry and those dealing in insect-plant interactions.