The third edition of this text contains key improvements and changes that continue to provide intuctors and student with the bestinformation technology auditing text available. This edition has been reorganized and expanded to addres the internal control and audit issues mandated by Sarbanes-Oxley legislation. The third edition include a full ranges of new and revised homework assignments, up to date content changes, a new chapter on transaction processing, and new appedix material in several chapter to provide the reader with background and perspective. All of these changes add up to more student and instructors as current as possible on issues such as business processes, general controls, aplication controls, fraud issues, and relevant aspects of Sarbanes-Oxley legistation in a changing IT auditing environment.