The goal of this review is to introduce the reader to the ideas behind the eugenic movement, its implementation, and its consequences. First, we address the work of prominent 19th century forerunners of eugenics. Second, we discuss the eugenic movement during the first half of the 20th century, and its common and differential characteristics in countries where its expression was more marked, including the US and Nazi Germany. We also discuss the eugenic movement in Sweden, whose history has remained unknown until recently. We analyze the reasoning behind forced sterilization and involuntary euthanasia. Finally, we consider the impact that past eugenics has had on the profession of psychiatry and psychiatric research, particularly genetics. We argue that the history of the 20th century eugenics movement and its leaders still require attention.