The field of androgen excess disorders has advanced substantially since the original publication of this book. The Androgen Excess Society (AES) was founded to bring together investigators in the field. A better understanding of the screening, progression, and molecular genetics of nonclassic adrenal hyperplasia (NCAH) has improved the clinical care and diagnostic accuracy of these patients. New criteria for the diagnosis of the polycystic ovary syndrome (PCOS) were proposed in Rotterdam, criteria that have resulted in controversy and, hopefully, initiation of new studies. The association of insulin resistance with PCOS has been strengthened, and the role of metformin in tre- ing the infertility of the PCOS has been validated. Risks for diabetes and, more cont- versially, cardiovascular disease in women with PCOS have received substantial investigation. Our understanding of the epidemiology and economic impact of these disorders has expanded, emphasizing their critical importance. These are but a few highlights of how the terrain has changed in a relatively brief period of time. In keeping with these advances, the title of this book has been revised to reflect the growing importance of PCOS as the most prevalent androgen excess disorder in women, and arguably, as the one that might have the most serious adverse consequences for general health. There are fewer chapters to provide a more focused elucidation of the area. Several chapters were penned by new (and young) authors who are conducting cutting-edge research in the field.