German serial killer whose widely analyzed career influenced European society's understanding of serial murder, sexual violence, and sadism in the first half of the 20th century.

Kürten, the third of 13 children, experienced a violent childhood. His father, an abusive alcoholic, was imprisoned for three years for attempting to molest Kürten's 13-year-old sister. Before he was 10 years old, Kürten had apparently murdered two schoolmates. During his teenage years he committed numerous petty crimes, and by the time of his last arrest he had been sentenced to prison nearly 30 times. In the Düsseldorf area from February to November 1929, he committed a series of brutal and sadistic murders.

Kürten's trial became a national event, attracting many academic observers as well as the merely curious. He candidly recounted details of his crimes to the celebrated psychologist Karl Berg, whose The Sadist (1932) became a classic of criminological literature. According to Berg, Kürten was a sexual psychopath and his crimes represented a perfect example of Lustmord, or murder for pleasure. At his trial on nine counts of murder and seven counts of attempted murder, Kürten was placed in a special cage to prevent his escape. He was sentenced to death and executed by guillotine.

Berg's biography of Kürten would ultimately influence all subsequent scholarship on serial murder. The case also had an impact on popular culture, serving as the basis of Fritz Lang (Lang, Fritz)'s film M (1931), in which a Kürten-like character is memorably portrayed by Peter Lorre (Lorre, Peter).