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.