In 1876 Lombroso published L'Uomo delinquente, (Criminal Man), which he later expanded into a multi-volume work. Lombroso measured the shape and size of criminals' heads, and concluded that they displayed atavistic traits that were throwbacks to primitive man. In effect, what Lombroso had created was a new pseudoscience of forensicphrenology. Lombroso concluded that the criminals were born with inherited anti-social traits. His work on this was later pulled into the context of eugenics and other "scientific racism," which had many consequences in the first half of the twentieth century.
Lombroso also advocated humane treatment for criminals. He argued for making rehabilitiation as the chief goal of penology, and against the routine employment of capital punishment.