The main changes in this edition are in Part two. The old Chapter 8 (“BCH, Goppa, and Related Codes”) has been revised and expanded into two new chapters, numbered 8 and 9. The old chapters 9, 10, and 11 have then been renumbered 10, 11, and 12. The new Chapter 8 (“Cyclic codes”) presents a fairly complete treatment of the mathematical theory of cyclic codes, and their implementation with shift register circuits. It culminates with a discussion of the use of cyclic codes in burst error correction. The new Chapter 9 (“BCH, Reed–Solomon, and Related Codes”) is much like the old Chapter 8, except that increased emphasis has been placed on Reed-Solomon codes, reflecting their importance in practice. Both of the new chapters feature dozens of new problems.