The only man I ever met whose ambition was to be a suicide bomber was an inmate at the British prison where I worked as a doctor in the 1990s and 2000s. He was a career criminal of very nasty propensities whose father was Arab and mother English. He had reached his 30s, the age at which criminals usually turn away from crime in favor of something better—in his case the killing of as many infidels as possible, along with himself.

Coming to religion is one reason, or pretext, for abandoning crime. In the prison there was much...