In this issue of Urologic Clinics of North America, guest editor Dr. Kevin R. Loughlin brings his considerable expertise to the topic of Testosterone. With about 2 out of 10 men older than 60 years having low testosterone (American Urological Association), coupled with an aging population, this issue is an important resource for all urologists for effectively treating men and improving outcomes. It provides a current update on testosterone in men from top experts in the field, covering prostate cancer treatment, the use of anabolic steroids, hypogonadism, testosterone replacement, and more. Contains 15 practice-oriented topics including current management and controversies surrounding andropause; testosterone and male sexual function; the interplay of testosterone and dihydrotestosterone in prostate cancer; and more.  Provides in-depth clinical reviews on testosterone, offering actionable insights for clinical practice.  Presents the latest information on this timely, focused topic under the leadership of experienced editors in the field. Authors synthesize and distill the latest research and practice guidelines to create clinically significant, topic-based reviews.