Chemical signals among organisms form a vast communicative interplay, fundamental to the fabric of life, in the words of one expert. Chemical ecology is the discipline that seeks to understand these interactions - to use biology in the search for new substances of potential benefit to humankind. This book highlights selected research areas of medicinal and agricultural importance. Leading experts review the chemistry of: insect defense and its applications to pest control; phyletic dominance - the survival success of insects; social regulation, with ant societies as a model of multicomponent signalling systems; eavesdropping, alarm, and deceit - the array of strategies used by insects to find and lure prey; reproduction - from the gamete attraction to courtship and sexual selection; and the chemistry of intracellular immunosuppression. Topics also include the appropriation of dietary factors for defense and communication; the use of chemical signals in the marine environment; the role of the olfactory system in chemical analysis; and the interaction of polydnaviruses, endoparasites, and the immune system of the host.