Cesare Lombroso is known as the "Father of Criminology" or the "Father of Modern Criminology;" also the "founder of criminal anthropology." Cesare Lombroso took a positivist approach to the study of crime and criminology. Lombroso researched crime among individuals who had committed crimes. He studied the remains of executed individuals who had been convicted of crimes. 
Positivists rejected the notion of free-will and stated that "human behavior is actually pre-disposed and determined by individual and biological differences."
Through his studies he felt that those most prone to criminal acts were men rather than women because they had more testosterone than women; and also they were men who had larger heads and were more muscular than the average male. Therefore he felt that men who committed crime were like the "savages" of old.
Lombroso believed that those who committed crimes were not only "genetic throwbacks," but also of "inborn criminality." In other words, because of their features and muscular structure they were predisposed to committing crime.
According to Lombroso, his theory of criminality was one of "atavism" or a " reversion to savagery." "Criminals are throwbacks to a primitive stage of human evolution." Lombroso's evolutionary theory closely followed the evolutionary theory of Charles Darwin.
Lombroso's positivist approach was scientific, anthropological and biological, not taking into consideration the effects of a person's environment of parental upbringing. However Lombroso didn't totally reject all other causes of crime, but in later works reformulated some of his theories. Much is yet to be learned about the theories of Cesare Lombroso; and there is current research regarding his works. He wrote extensively and much of his writing has not been translated from the Italian.
Although Lombroso is regarded as the founder of criminology since with his research the "legalistic concern for crime" graduated to a "scientific study of the criminal," which in turn became the field of criminology, which is an offshoot of sociology, his theories have largely been abandoned today with more emphasis placed on the environment in which a person grows rather than a hereditary or genetic approach. However some criminologists still do defend some of his theories, and there is also a switch back to some of his ideas.
Criminology as with all sciences is continually being researched and studied to find the most up-to-date and true hypothesis. Therefore making criminology a science was the ultimate contribution to the field of criminology by Cesare Lombroso.
Some books written by Lombroso are "Criminal Woman, the Prostitute, and the Normal Woman," "Criminal Man," "The Female Offender," and "The Man of Genius." You can find these books at Amazon.com including many others written by Lombroso, but not yet translated.
Also there are books written about Lombroso by Professor Gibson at Cuny.Edu. Those immersed in the field of criminology do take Cesare Lombroso and his findings seriously even if not all of his theories are still used today.
There is also an anthropological museum in Italy dedicated to the works of Cesare Lombroso.
1) Weiten, Wayne, Psychology, 6th ed., Wadsworth, 2005.