Lombroso's general theory suggested that criminals are distinguished from noncriminals by multiple physical anomalies.
He postulated that criminals represented a reversion to a primitive or subhuman type of person characterized by physical features reminiscent of apes, lower primates, and early humans and to some extent preserved, he said, in modern "savages".
The behavior of these biological "throwbacks" will inevitably be contrary to the rules and expectations of modern civilized society.

Through years of postmortem examinations and anthropometric studies of criminals, the insane, and normal individuals, Lombroso became convinced that the "born criminal" (reo nato, a term given by Ferri) could be anatomically identified by such items as a sloping forehead, ears of unusual size, asymmetry of the face, prognathism, excessive length of arms, asymmetry of the cranium, and other "physical stigmata".
Specific criminals, such as thieves, rapists, and murderers, could be distinguished by specific characteristics, he believed.
Lombroso also maintained that criminals had less sensitivity to pain and touch; more acute sight; a lack of moral sense, including an absence of remorse; more vanity, impulsiveness, vindictiveness, and cruelty; and other manifestations, such as a special criminal argot and the excessive use of tattooing.

Besides the "born criminal", Lombroso also described "criminaloids", or occasional criminals, criminals by passion, moral imbeciles, and criminal epileptics.
He recognized the diminished role of organic factors in many habitual offenders and referred to the delicate balance between predisposing factors (organic, genetic) and precipitating factors such as one's environment, opportunity, or poverty.

In Criminal Woman, as introduced in an English translation by Nicole Hahn Rafter and Mary Gibson, Lombroso used his theory of atavism to explain women's criminal offending.
In the text, Lombroso outlines a comparative analysis of "normal women" opposed to "criminal women" such as "the prostitute."
However, Lombroso's "obdurate beliefs" about women presented an "intractable problem" for this theory: "Because he was convinced that women are inferior to men Lombroso was unable to argue, based on his theory of the born criminal, that women's lesser involvement in crime reflected their comparatively lower levels of atavism."

Lombroso's research methods were clinical and descriptive, with precise details of skull dimension and other measurements.
He did not engage in rigorous statistical comparisons of criminals and non-criminals.
Although he gave some recognition in his later years to psychological and sociological factors in the etiology of crime, he remained convinced of, and identified with, criminal anthropometry.
 After he died, his skull and brain were measured according to his own theories by a colleague as he requested in his will; his head was preserved in a jar and is still displayed with his collection at the Museum of Psychiatry and Criminology in Turin.

Lombroso's theories were disapproved throughout Europe, especially in schools of medicine: notably by Alexandre Lacassagne in France.
His notions of physical differentiation between criminals and non-criminals were seriously challenged by Charles Goring (The English Convict, 1913), who made elaborate comparisons and found insignificant statistical differences.
Lombroso's general theory suggested that criminals are distinguished from noncriminals by multiple physical anomalies. He postulated that criminals represented a reversion to a primitive or subhuman type of person characterized by physical features reminiscent of apes, lower primates, and early humans and to some extent preserved, he said, in modern "savages". The behavior of these biological "throwbacks" will inevitably be contrary to the rules and expectations of modern civilized society.
Through years of postmortem examinations and anthropometric studies of criminals, the insane, and normal individuals, Lombroso became convinced that the "born criminal" (reo nato, a term given by Ferri) could be anatomically identified by such items as a sloping forehead, ears of unusual size, asymmetry of the face, prognathism, excessive length of arms, asymmetry of the cranium, and other "physical stigmata". Specific criminals, such as thieves, rapists, and murderers, could be distinguished by specific characteristics, he believed. Lombroso also maintained that criminals had less sensitivity to pain and touch; more acute sight; a lack of moral sense, including an absence of remorse; more vanity, impulsiveness, vindictiveness, and cruelty; and other manifestations, such as a special criminal argot and the excessive use of tattooing.
Besides the "born criminal", Lombroso also described "criminaloids", or occasional criminals, criminals by passion, moral imbeciles, and criminal epileptics. He recognized the diminished role of organic factors in many habitual offenders and referred to the delicate balance between predisposing factors (organic, genetic) and precipitating factors such as one's environment, opportunity, or poverty.
In Criminal Woman, as introduced in an English translation by Nicole Hahn Rafter and Mary Gibson, Lombroso used his theory of atavism to explain women's criminal offending. In the text, Lombroso outlines a comparative analysis of "normal women" opposed to "criminal women" such as "the prostitute." However, Lombroso's "obdurate beliefs" about women presented an "intractable problem" for this theory: "Because he was convinced that women are inferior to men Lombroso was unable to argue, based on his theory of the born criminal, that women's lesser involvement in crime reflected their comparatively lower levels of atavism."
Lombroso's research methods were clinical and descriptive, with precise details of skull dimension and other measurements. He did not engage in rigorous statistical comparisons of criminals and non-criminals. Although he gave some recognition in his later years to psychological and sociological factors in the etiology of crime, he remained convinced of, and identified with, criminal anthropometry.  After he died, his skull and brain were measured according to his own theories by a colleague as he requested in his will; his head was preserved in a jar and is still displayed with his collection at the Museum of Psychiatry and Criminology in Turin.
Lombroso's theories were disapproved throughout Europe, especially in schools of medicine: notably by Alexandre Lacassagne in France. His notions of physical differentiation between criminals and non-criminals were seriously challenged by Charles Goring (The English Convict, 1913), who made elaborate comparisons and found insignificant statistical differences.
Cesare Lombroso