Developed from the keynote addresses delivered at the third IOBC International Symposium (co-organized with CILBA) held in Montpellier in October 2002, this book follows the themes of: 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 enemies, and genetic manipulation of natural enemies. New issues for each of the major approaches in applied biological control are discussed and include: the use of molecular genetics to trace the origin of target pests in classical biological control; the potential of mass-reared, transgenic agents in augmentative biological control; and the compatibility of transgenic crops and natural enemies in conservational biological control.