Do psychopaths enjoy reading books about psychopaths? In his engagingly irreverent new best seller, The Psychopath Test: A Journey Through the Madness Industry (Riverhead, $25.95), the journalist Jon Ronson notes that only about one in 100 people are psychopaths (there is a higher proportion in prisons and corporate boardrooms), but he wonders if this population will be overrepresented among readers of his book. After all, people do enjoy learning about themselves, and psychopaths in particular have an enhanced sense of their own importance. And they might like what Ronson has to say. He approvingly quotes experts who argue that psychopaths make “the world go around.” Despite their small numbers, they cause such chaos that they remold society — though not necessarily for the better.

If you aren’t sure whether you are a psychopath, Ronson can help. He lists all the items on the standard diagnostic checklist, developed by the psychologist Robert Hare. You can score yourself on traits like “glibness/superficial charm,” “lack of remorse or guilt,” “promiscuous sexual behavior” and 17 other traits. As one psychologist tells Ronson, if you are bothered at the thought of scoring high, then don’t worry. You’re not a psychopath.

One of the traits on the checklist is “callous/lack of empathy.” This is the focus of another new book, The Science of Evil: On Empathy and the Origins of Cruelty (Basic Books, $25.99), by Simon Baron-Cohen, a Cambridge psychologist best known for his research on autism. Baron-Cohen begins by telling how, at the age of 7, he learned that the Nazis turned Jews into lampshades and bars of soap, and he goes on to provide other examples of human savagery. To explain such atrocities, he offers an ambitious theory grounded in the concept of empathy, which he defines as “our ability to identify what someone else is thinking or feeling and to respond to their thoughts and feelings with an appropriate emotion.” For Baron-Cohen, evil is nothing more than “empathy erosion.”

Now, one might lack empathy for temporary reasons — you can be enraged or drunk, for instance — but Baron-Cohen is most interested in lack of empathy as an enduring trait. Once again, you might want to know where you stand, and Baron-­Cohen ends his book with a 40-question Empathy Quotient checklist.