Nazi Germany was heir to a highly scientized system of medicine, and saw a colossal rise in coerced medical experiments and other forms of exploitative, non-consensual research. The experiments and coerced research took multiple forms, but the scale under Nazism was unprecedented, finding a parallel only in the more centralised organisation of Japanese military medical experiments on Chinese civilians and Allied prisoners of war. The experiments and associated forms of coerced research have remained in public understanding as among the worst Nazi atrocities. Yet for many years they were marginalised as "pseudo-science", so that they were disconnected from mainstream German medical science and academia. "Medical experiments" occurred in a variety of clinics and other medical locations in addition to large-scale concentration camp experiments and the plethora of small-scale experiments in camps and clinics. The chapter also presents an overview of the key concepts discussed in this book.