This book aims to address a number of controversies concerning the use of testosterone treatment. It explains topics that clinicians regularly encounter such as whether to use free or total testosterone in the evaluation of the patient with testosterone deficiency; what factors actually impact testosterone levels, polycythemia, gynecomastia, bone density, and hyperprolactinemia in the testosterone deficient patient; critical analysis of the numerous questionnaires that are available to clinicians; and the impact of testosterone therapy on male fertility, cardiovascular disease, and prostate events including prostate cancer. Guiding the reader in both evaluation and management, the book also illuminates novel concepts in the T space such as testosterone use in the transgender population, T therapy as an endothelial modulator, bipolar testosterone therapy in the patient with advanced prostate cancer, and testosterone therapy as a performance enhancer. Controversies in Testosterone Deficiency is intended for any clinician involved in the care of patients with testosterone deficiency, exploring hot topics and correcting existent misinformation in the routine care of patients.