The decade that has passed since publication of the second edition of this textbook has not only witnessed a tremendous increase in knowledge within the ? eld of and- logy, but also seen the ? eld itself achieve a newfound status within the medical p- fession. Knowledge and status have been of mutual bene? t to the ? eld and the growing critical mass of diagnostic and therapeutic possibilities have caused andrology to be recognized as a medical subspecialty in some countries such as Germany, Poland, and Estonia. The European Academy of Andrology (EAA) served as a pacemaker for this development and continues to strive for establishment of andrology as a clinical ? eld. Well-designed curricula and qualifying examinations have contributed to the of? cial recognition of andrology as a speciality. This recognition of the ? eld helps patients with andrological problems to ? nd the specialist they seek. This textbook summarizes the current state of knowledge in the ? eld of andrology. It is a source of knowledge to all those who are or want to become andrologists. In addition, as andrology is clearly an interdisciplinary ? eld, this book may serve as a compendium and source of reference for all those physicians and biologists active in neighboring areas, who want to obtain an overview of andrology and who require information on special problems. The extensive references are timely and up to date.