In 1935, a Portuguese neurologist developed the lobotomy. The operation was intended to alleviate severe mental disorders but faced harsh criticism within the medical community. It broke a taboo by directly intervening in the brain and altering the patients' personalities. However, after the end of World War II, the procedure became widely adopted. As the number of psychosurgical interventions rapidly increased, new opportunities for research emerged. It was claimed that lobotomy relieved the emotional tension of the mentally ill, even proving effective in hopeless cases, and alleviated the burden on both institutional psychiatry and society. Although experts began to view the method with increasing skepticism throughout the 1950s, the era of lobotomy only came to an end when psychiatry faced growing public criticism around 1970. Marietta Meier examines this history.