This book presents a subselection of papers presented at the ECAI 2000 Workshop on Balancing Reactivity and Social Deliberation in Multi-Agent Systems together with additional papers from well-known researchers in the field. The 13 revised full papers were carefully reviewed and selected for inclusion in the present book. Besides two introductory survey papers, the book offers topical sections on architectures and frameworks, enhanced reactivity, and controlled social deliberation.