Trellis decoding of block codes has attracted huge attention from specialists working in the area of error-control coding, since the technique has the potential of significant performance improvement in existing communication and information systems, such as mobile and personal radio systems, magnetic and optical storage devices, etc. The material in the book is based on the research carried out by the authors during the last five years. It is suitable for use in information theory, error-control coding and electronics communications courses. It is also of interest to telecommunications companies, research and development organisations and defence contractors. Key features include: An introduction to the problem and review of previous works; Construction of codes with optimum coordinate reordering; Trellis design procedures for both the syndrome and coset trellises; Application of trellis decoders in communication systems.