What is the theme in Without Conscience: The Disturbing World of the Psychopaths Among Us by Robert D. Hare?

Identifying a psychopath is the main theme of the book. This is perhaps the most important theme in the entire book. Hare spends over half of the book emphasizing the importance of correct diagnoses and evaluation of psychopathy. The development and evolution of the Psychopathy Checklist is the first step in finding a scientific, valid tool in which to measure psychopathy.