Ronald Knox’s Double Cross Purposes

Double Cross Purposes (published in 1937) was, alas, the last of Ronald Knox’s detective novels. And it’s a treat for fans of this underrated author.

Monsignor Ronald Knox (1888-1957) as a Catholic priest and theologian who wrote detective stories as a hobby. He was a founding member of the Detection Club and is well known for his Ten Commandments of Detective Fiction in which he laid down the rules he felt should be followed by writers of this genre of fiction. 

He wrote six detective novels, five of which feature Miles Bredon. Bredon is a private detective employed by the Indescribable Insurance Company. This company plays a significant role in the novels, with many of the plots being driven the company’s practice of issuing some very unusual policies. The Indescribable prides itself on being prepared to insure just about anything. In Double Cross Purposes the company has written a policy insuring a treasure hunter against fraud on the part of his partner, and given the nature of his partner fraud seems rather likely. That’s why the Indescribable has asked Bredon to travel to the Scottish Highlands to keep on the mismatched pair of treasure seekers.

The Honourable Vernon Lethaby is the son of a peer. He is a notorious young man-about-town. He has no money of his own and is reliant on his aunt in order to maintain his flamboyant lifestyle. He has teamed up with the even more disreputable Digger Henderson. Digger is a Canadian ex-bootlegger who has attracted the notice of the police forces of most of the countries in which he has resided. The idea of the treasure hunt is inspired by Lethaby’s dim childhood recollections of a map that used to hang in the family seat, Dreams Castle, in Scotland. He believes that the map shows the location of a treasure secreted away by Bonnie Prince Charlie after the ’45. Local legends speak of this treasure but no-one tales them very seriously. It seems hardly likely that any treasure actually exists but it’s always possible and in any case it’s the sort of adventure that appeals to Lethaby. And even if there is no treasure there might still be a way to make some admittedly rather dishonest money out of what promises to be an amusing lark.

The treasure is reputed to be buried on an island in the river Dounie. Lethaby and Digger have rented the house (the one and only house) on the island. The house and the island have passed out of the hands of Lethaby’s family but the present owner, Sir Charles Airdire (who also now owns Dreams Castle), is willing to offer them a lease on the understanding that since the treasure if it exists is on his land he will get a half share.

Miles Bredon and his wife Angela have meanwhile taken up residence in a cottage opposite the island where they can keep watch on the treasure hunters. They have been joined by Mr Pulteney, an elderly schoolmaster who also appears in one of the earlier Miles Bredon mysteries (The Three Taps). 

Miles is not quite certain what to expect but he is certainly taken considerably by surprise when a murder occurs on the island. It’s all rather puzzling since the identity of the victim is far from certain.

Knox’s plots tend to be very much on the convoluted side. They also tend towards the far-fetched, but this is very much in keeping with the author’s view of the detective story as an elaborate intellectual game. Knox would have made no apologies for making the puzzle plot the heart of his tales. He wrote the kinds of detective stories that modern critics despise, which of course explains why they’re so much fun. While his plotting stretches credibility it’s also genuinely and delightfully ingenious.

Knox had more going for him than just his skill at constructing puzzle plots. His writing style was fluent, literate and very witty. He had a knack for creating rather outrageous characters who nonetheless come across as living breathing human beings. Miles and Angela Bredon are one of the more likeable detective couples and their verbal sparring provides plenty of amusement. The shrewd but pompous Mr Pulteney provides even more humour.

Double Cross Purposes is certainly not meant to be taken too seriously. Knox wrote detective stories because he enjoyed doing so and the reader should derive just as much enjoyment from reading them as Knox derived from writing them. Highly recommended.