The Handbook of Logic in Computer Science is a multi-volume work covering all the major areas of the application of logic to theoretical computer science. It comprises six volumes, each containing five or six chapters giving an in-depth overview of one of the major topics in the field. The handbook is the result of many years of cooperative effort by eminent researchers in the area, and will no doubt be the standard reference work in logic and theoretical computer science for years to come. Volume 4: Semantic Modelling covers the fundamental topics of semantic modelling in logic and computation. Contents include models for concurrency, concrete process algebra, correspondence between operational and denotational semantics, effective algebras, and abstract interpretation.