This book is the seventh in the successful line of Intelligent Agents volumes published in LNAI. It is based on the seventh workshop on Agent Theories, Architectures, and Languages, ATAL '99, held in Boston, MA, USA in July 1999. The 21 revised full papers included were selected from a total of 71 submissions during two rounds of reviewing. Also included are one panel summary and the statements of panelists participating in another panel held during ATAL 2000. The book is divided into topical sections on agent theories; agent development tools and platforms; models of agent communication and coordination; autonomy and models of agent coordination; agent languages; and planning, decision making, and learning. This state-of-the-art survey is essential reading for anyone interested in agent technology.