This is an introductory text in number theory from a well-known name ... it covers most of the material traditionally expected in such a course. ... One of the most interesting features of this book is the extensive (and crunchy) biographical sketches of relevant mathematicians (both living and dead). ... I heartily recommend this book to undergraduates and the passing layman, as it is the work of a master and is lucidly explained. ... -IACR book reviews, March 2010 The second edition of this very interesting book includes a revision of its contents and a pledge for the publication of a second volume with advanced material for a second course in number theory. -Panayiotis Vlamos, Zentrablatt Math, 1175 Praise for the First Edition ...a very useful addition to the many books on number theory with applications, and it is meant to be accessible to anyone from the novice to the research scientist ... [it] provides an excellent supplementary source of information for the reader, not least in the many biographical footnotes on the mathematicians involved in the subject matter, and there are also more than a thousand exercises and examples in the text. ... -P. Shiu, Zentralblatt MATH, Vol. 943