A practical guide to the importance of testosterone for health, the consequences of deficiency and the options for restoring hormonal balance by a doctor who needed TRT to reclaim his life. Over the past few decades, average testosterone levels have been declining at an alarming rate, even when adjusted for age. Deficiency impacts not only fertility and muscle mass, as is generally recognised, but all aspects of physical, mental and emotional health. Furthermore, it can affect the epigenetics of a man's future children – low testosterone today may set the stage for even greater hormonal and metabolic dysfunction in the next generation. This book provides a structured overview and distillation of what the author had to learn through his own research, clinical practice, patient experience and personal journey because this was not part of his medical training or education. His book goes beyond symptom lists and blood test results (both controversial) to provide a roadmap for the individual to understand testosterone's central role in their development, health and identity.