Unsolved Problems in Number Theory contains discussions of hundreds of open questions, organized into 185 different topics. They represent numerous aspects of number theory and are organized into six categories: prime numbers, divisibility, additive number theory, Diophantine equations, sequences of integers, and miscellaneous. To prevent repetition of earlier efforts or duplication of previously known results, an extensive and up-to-date collection of references follows each problem. In the second edition, not only extensive new material has been added, but corrections and additions have been included throughout the book.

From reviews of the first edition:"...many talented young mathematicians will write their first papers starting out from problems found in this book." Mathematical ReviewsMathematics is kept alive by the appearance of new unsolved problems, problems posed from within mathematics itself, and also from the increasing number of disciplines where mathematics is applied. This book provides a steady supply of easily understood, if not easily solved, problems which can be considered in varying depths by mathematicians at all levels of mathematical maturity.

Includes supplementary material: sn.pub/extras

Inhalt
A. Prime Numbers.- B. Divisibility.- C. Additive Number Theory.- D. Diophantine Equations.- E. Sequences of Integers.- F. None of the Above.- Index of Authors Cited.- General Index.