The dramatic increase in research in recent years shows that logic is now widely recognized as one of the foundational disciplines of computing and has found applications in virtually all aspects of the subject, from software engineering and hardware to programming languages and artificial intelligence. The Handbook of Logic in Artificial Intelligence and Logic Programming was created in response to the growing need for an in-depth survey of these applications, and as a result is a unique and invaluable reference source. The Handbook comprises five volumes, each an in-depth overview of one of the major topics in this area. It is the result of years of cooperative effort by internationally renowned researchers in the field, and will no doubt be the standard reference work in AI for years to come. Volume IV covers, among other subjects, epistemic reasoning, time and change for AI, and temporal nonmonotonic reasoning.