The participants of the Second Review Conference of the parties to the Biological Weapons Convention agreed on instituting voluntary confidence-building measures (CBMs) to strengthen the Convention. For this book SIPRI has gathered together experts in the fields of disarmament, epidemiology, molecular genetics, and virology. They evaluate the extent to which these CBMs contribute to preventing or reducing the occurrence of ambiguities, doubts, and suspicions which might be raised about compliance with the BW convention, and how CBMs contribute to improving international co-operation in the field of peaceful biological activities.