"Continuing in a great tradition of publishers, editors, and authors, we proudly present to you, our readers, the twelfth edition of the "Bible of Urology"-- Campbell-Walsh-Wein Urology . Started in 1954 as Campbell's Urology and retitled Campbell-Walsh Urology in 2012, the present editors felt it was appropriate to honor Alan J. Wein, MD, PhD (Hon) for his many years of dedication to this text by adding his name to the previous chief editors. During his time as chief editor, Dr. Wein was responsible for keeping the textbook in pace with a rapidly growing field in medicine--for this diligence and dedication we are grateful. As with previous editions, the twelfth edition presents many exciting advances in our use and understanding of technology, physiology, pharmacology, epidemiology, and pathophysiology while maintaining our basic classical urological knowledge"--Preface.