Research on testosterone is increasing in many senses; however there is still much controversy regarding its physiology and clinical use. This book addresses these topics, providing a broad over­view about testosterone, from its basic fea­tures to the most recent evidence of clin­ical applicability. Also, specific conditions in which testosterone play a pivotal role are discussed in detail, such as hypogonadism, misuse and abuse, puberty, cardiovascular effects and testosterone therapy. Although not essential for survival, testosterone represents the essence of male biological function, being the important testicular androgen in men. Low serum testosterone levels are asso­ciated with cardiovascular morbidity, meta­bolic syndrome, type 2 diabetes mellitus, atherosclerosis, osteoporosis, sarcopenia, and mortality. Conversely, increased serum levels of testosterone may lead to deleteri­ous events. In general, there is increasing evidence that serum testosterone is a major biomarker status of men’s health in general.Testosterone: From Basic to Clinical Aspectsis an indispensable reference for all those who seek state-of-the-art knowledge regarding this hormone, from basic issues (including pharma­cology and physiology) through clinical aspects (related diseases and supplementation ther­apy).