This book most fully covers all the main methods of secretly obtaining information and methods of protection against industrial espionage. The encyclopedic nature of the presented material, consideration of a wide range of aspects of information security make this publication a reference book for representatives of government agencies and security officers, teachers, students and other persons concerned with the problem of information security. The book can be used as a textbook and as a reference book for specialists with practical work experience. We hope that it will also be of interest to people who are encountering this problem for the first time.