This book has been developed from the keynote addresses delivered at the third IOBC International Symposium (co-organized with CILBA) that was held in Montpellier in October 2002, to address recent developments in genetics and evolutionary biology as applied to biological control. Chapters are organized around the following themes: Genetic structure of pest and natural enemy populations, Molecular diagnostic tools in biological control, Tracing the origin of pests and natural enemies, Predicting evolutionary change in pests and natural enemies Compatibility of transgenic crops and natural enemie, Genetic manipulation of natural enemies. The authors identify new issues for each of the major approaches in applied biological control. These include the (1) use of molecular genetics to trace the origin of target pests in classical biological control, (2) potential of mass-reared, transgenic agents in augmentative biological control, and (3) compatibility of transgenic crops and natural enemies in conservational biological control.