This best-selling, easy-to-read, communication systems text continues to include the most comprehensive coverage of digital communications in an undergraduate level text in this fourth edition.  In addition to being the most up-to-date communications text available, Simon Haykin has added more MATLAB computer experiments and improved examples and problems throughout. Intended for use in the Communication Systems course in the Electrical Engineering core curriculum. This course is typically offered at the junior/senior level in electrical engineering departments at the majority of four year colleges and universities that have electrical engineering programs. The introductory course in communication systems is required for electrical engineering majors. This text will also appeal to a small segment of the professional engineering market.