This book contains a complete detailed description of two classes of special numbers closely related to classical problems of the Theory of Primes. There is also extensive discussions of applied issues related to Cryptography. In Mathematics, a Mersennenumber (named after Marin Mersenne, who studied them in the early 17-th century) is a number of the form Mn = 2n - 1 for positive integer n. In Mathematics, a Fermat number (named after Pierre de Fermat who first studied them) is a positive integer of the form Fn = 2k+ 1, k = 2n, where n is a non-negative integer. Mersenne and Fermat numbers have many other interesting properties. Long and rich history, many arithmetic connections (with perfect numbers, with construction of regular polygons etc.), numerous modern applications, long list of open problems allow us to provide a broad perspective of the Theory of these two classes of special numbers, that can be useful and interesting for both professionals and the general audience-- Deza offers a complete detailed description of two classes of special numbers that are closely related to classical problems of the Theory of Primes. She also discusses in depth applied issues related to cryptography. A Mersenne number takes the form Mn=2-1 for positive integer , she says, and a Fermat number is a positive integer in the form F/=2/=1, =2/, where is a non-negative integer. She discusses each in turn, as well as prime numbers and modern applications. Annotation ©2022 Ringgold, Inc., Portland, OR (protoview.com)