""A very welcome addition to books on number theory.""-Bulletin of the American Mathematical Society.Clear and detailed in its exposition, this text can be understood by readers with no background in advanced mathematics, and only a small part requires a working knowledge of calculus. Topics include divisibility theory, important number-theoretic functions, basic properties of congruences as well as congruences in one unknown and of the second degree, and primitive roots and indices. One of the most valuable characteristics of this book is its emphasis on learning number theory by means of demonstrations and problems. More than 200 problems and full solutions appear in the text, plus 100 numerical exercises. Some of these exercises deal with estimation of trigonometric sums and are especially valuable as introductions to more advanced studies.
