Galen's Health (De sanitate tuenda) was the most important work on daily exercise, diet and health regimes in antiquity. This book presents the first reliable scholarly translation of this work in English, alongside the related theoretical work Thrasybulus. A substantial introduction and thorough annotation elucidate both works and contextualize them within the framework of ancient health practices, ancient conceptions of the body and debates between medical and philosophical schools. The texts are of enormous interest from three points of view: (1) the wide range of insights they give into ancient everyday lifestyles, especially as regards diet, bathing, exercise and materia medica, as well as aspects of daily intellectual life; (2) the light they shed on ancient debates within medicine and philosophy, on fundamental conceptions of the body and the relationship between body and mind; (3) the enormous influence that Health had in mediaeval and early modern times.