This text is intended as a practical guide for physicians and surgeons who treat diseases of the breast, both benign and malignant. Thus, general surgeons, internists, family practitioners, gynecologists, surgical oncologists, radiation oncologists, and medical oncologists will find this book useful. The management of breast diseases requires a multidisciplinary approach, and this textbook therefore includes the views of a wide range of specialists from throughout the world. Today the treatment of breast diseases is largely predicated on the results of randomized prospective trials. The results of many clinical trials are discussed in detail, and readers will find this book to be a useful guide to the evidence-based treatment of breast diseases. The revised edition provides a comprehensive update of the previous version of the book. Specifically, it contains 2 new chapters: “Molecular Classification of Breast Cancer” and “Breast Cancer Molecular Testing for Prognosis and Prediction”. In addition, since publication of the previous edition, the results of numerous adjuvant systemic therapy and neo-adjuvant systemic therapy trials have been published, and this edition provides a comprehensive overview of these trials and discusses how they have changed the management of breast cancer. Similarly, there have been, in the last few years, important new developments in the local therapy of breast cancer. This edition discusses these new developments and particularly recent developments and controversies concerning the management of the axilla in patients with primary breast cancer. New guidelines with respect to radiotherapy are also reviewed and discussed. Finally, all chapters in the book are thoroughly revised and updated to provide readers with current understanding of the biology and treatment of breast cancer.