It wasn't so much that Christmas Calvert liked killing people, he was just very good at it. A crack shot, he also possessed an unnatural ability to distance himself from his actions, to shut off all emotion when 'vanishing' his targets. His exceptional shooting skills soon brought him to the attention of Colonel Dansey, and when an RAF doctor classified Calvert as 'remarkably amoral', Dansey was left in no doubt that he had found a new recruit for The Button Squad.
John William Wainwright was a rear gunner in World War II, after which he spent twenty years as a policeman in Yorkshire. He wrote eighty crime novels between 1965 and 1992, sometimes under the pseudonym 'Jack Ripley'. He also wrote some short stories (mostly uncollected in book format), 7 radio plays, and an indefinite amount of magazine articles and newspaper columns.