Logic is now widely recognized as one of the foundational disciplines of computing, and its applications reach almost every aspect of the subject, from software engineering and hardware to programming languages and AI. The Handbook of Logic in Computer Science is a multi-volume work covering all the major areas of application of logic to theoretical computer science. The handbook comprises six volumes, each containing five or six chapters giving an in-depth overview of one of the major topics in field. It is the result of many years of cooperative effort by some of the most eminent frontline researchers in the field, and will no doubt be the standard reference work in logic and theoretical computer science for years to come. Volume 3: Semantic Structures covers all the fundamental topics of semantics in logic and computation. The extensive chapters are the result of several years of coordinated research, and each have a thematic perspective. Together, they offer the reader the latest in research work, and the book will be indispensable to anyone seriously involved in the subject.