The Mask of Sanity
Dandelion reminded me of a book that I'd like to call to your attention. It's called "The Mask of Sanity" by Dr. Hervey Cleckley, M.D., the seminal work on psychopathy.
You can download a copy in PDF format here. Right-click the link and choose "Save Target As...." in the popup menu.
I haven't read the whole thing, but I have read more than enough to know that it's packed with factual information about psychopaths.
The impression that I got is that his work and ideas fell into disfavor with the onset of the Great Society and that he is now being rediscovered in the light of the work by Dr. Robert Hare Ph.D.