This is a self-contained introduction to analytic methods in number theory, assuming on the part of the reader only what is typically learned in a standard undergraduate degree course. It offers to students and those beginning research a systematic and consistent account of the subject but will also be a convenient resource and reference for more experienced mathematicians. These aspects are aided by the inclusion at the end of each chapter of a section of bibliographic notes and detailed exercises. Professor Tenenbaum has emphasised methods rather than results, with the consequence that readers should be able to tackle more advanced material than is included here. Moreover, he has been able to cover developments on many new or unpublished topics such as: the Selberg-Delange method; a version of the Ikehara-Ingham Tauberian theorem; and a detailed exposition of the arithmetical use of the saddle-point method.