We have cruised along English canals and walked through the streets and monuments of Rome. His duties have taken us to an island off the coast of Normandy and to the backstage regions of several theatres. He has sailed with a psychopathic homicide from Tilbury to Cape Town and has made arrests in at least three country houses, one hospital, a church, a canal boat and a pub. Small wonder, perhaps, that we have both broadened our outlook under the pressure of these undertakings, none of which was anticipated on that wet afternoon in London.

At his first appearance he was a bachelor and, although responsive to the opposite sex, did not bounce in and out of irresponsible beds when going about his job. Or, if he did, I knew nothing about it. He was, to all intents and purposes, fancy-free and would remain so until, sailing out of Suva in Fiji, he came across Agatha Troy, painting in oils, on the boat-deck of a liner. And that was still some half-dozen books in the future.

There would be consternation shown by editors and publishers when, after another couple of jobs, the lady accepted him. The acceptance would be a fait accompli, and from then on I would be dealing with a married investigator, his celebrated wife, and later on, their son.

By a series of coincidences and much against his inclination, it would come about that these two would occasionally get themselves embroiled in his professional duties, but generally speaking he would keep his job out of his family life. He would set about his cases with his regular associate, who is one of his closest friends; Inspector Fox, massive, calm, and plain-thinking, would tramp sedately in. They have been working together for a considerable time, and still allow me to accompany them.

But “on the afternoon in question,” all this, as lady crime novelists used to say, “lay in the future.” The fire had burnt clear and sent leaping patterns up the walls of my London flat when I turned on the light, opened an exercise book, sharpened my pencil, and began to write. There he was, waiting quietly in the background ready to make his entrance at Chapter IV, page 58, in the first edition.