There is a significant increase in people who self-diagnose as having gender dysphoria and gender incongruence. The number of people with gender dysphoria and gender incongruence who seek assessment, support and treatment at gender identity clinic services has increased substantially over the years globally, and in Europe, North America and Australia in particular. Many countries lack appropriate transgender healthcare services. People with gender dysphoria and/or gender incongruence are often victimized and discriminated against. This book gives an overview regarding mental health and quality of life issues across the life span within the evolving interdisciplinary field of transgender healthcare. The book is written for professionals who in their day-to-day job may encounter people with gender dysphoria and gender incongruence; and for students, teachers, educators, academics, and members of the public at large with an interest in this timely topic. This book was originally published as a special issue of the International Review of Psychiatry.