Jon Ronson’s latest endeavour explores a particular form of madness: psychopathy, or sociopathy. This personality disorder occurs where the person appears normal but has an abnormal lack of empathy. Apparently, many people at the top of their professions have some psychopathic traits. Ronson attends a course on the Psychopathy Checklist – used by psychiatrists to assess a person’s mental state – and interviews a patient at Broadmoor Hospital claiming to be sane and a businessman alleged to have psychopathic tendencies. This is both an entertaining, wry commentary on the ‘madness industry’ and an insightful, enjoyable read.