Or to give its full title, The Seven Per Cent Solution Being a Reprint from the Reminiscences of John H. Watson, M.D., as edited by Nicholas Meyer (published 1975). It is of course a Sherlock Holmes pastiche and a clever and enjoyable one. Given recent news headlines, this is a somewhat timely blog for the seven per cent solution refers to the cocaine that Holmes inject. The novel begins with Watson’s realisation that Holmes has become hopelessly addicted and has descended into paranoid delusions in which he takes his old maths tutor, Professor Moriaty, to be a degenerate criminal mastermind. In collusion with Holmes’s brother, Mycroft, Watson tricks Holmes into going to Vienna, believing that he is on the track of Moriaty, and delivers him into the care of the foremost alienist of the day, no other than the young Sigmund Freud. What a brilliant idea this was, to build on Holmes’s tendency in the real Conan Doyle stories to resort to cocaine when bored and depressed between cases and to introduce a real historical character in the person of Freud, a detective of a very different kind, one devoted to solving the mysteries of the human mind. And Meyer does pretty much strike the authentic note. Freud invites Holmes to deduce his identity: ‘Holmes eyed him coldly.”Beyond the fact that you are a brilliant Jewish physician who was born in Hungary and studied for a time in Paris and that some radical theories of yours have so alienated the medical community . . . that you have ceased to practice medicine as a result, I can deduce little. You are married, possess a sense of honour . . .’ and so on. Despite their differences they are both acute observers of human behaviour and once Freud has cured Holmes of his addiction, they go on to solve a mystery together. The mystery itself is nothing special, but still the novel is a lot of fun and the end, in which Freud also uncovers the reason for Holmes’s hatred of Moriaty, is ingenious. I like a good Sherlock Holmes pastiche and this is among the better ones.