The Moving Finger starts off with the small village of Lymstock being plagued with a malicious campaign of anonymous letters, all hinting at sexual indiscretions. Tensions start to fray as everyone waits to see who will get the next letter. Finally, it seems like the letter-writer has gone too far when someone kills themselves after receiving a letter. Then, after the police are called in to investigate, the letter-writer strikes out to protect themselves from discovery by murdering a potential witness.

The story is told by Jerry Burton, an outsider to the village. Jerry is a pilot who was badly injured in a plane crash. When he is released from hospital, he retreats to this small, out of the way village to recuperate, accompanied only by his young, attractive sister, Joanna. He receives a note quite early in the book, accusing him and his sister of not really being brother and sister, and of having an illicit relationship. At first the pair think they have been targeted by a local who resents their intrusion in the village, but they soon find out their letter is only the latest in the letter-writer’s campaign. Their letter is typical of the anonymous writer: spiteful and malicious but with no basis to the accusation. This is why everyone is surprised when someone kills themselves. The letter, found near her body, appears to have no more factual basis than any of the others. But the victim is of a nervous disposition, and her action is put down to fear that no one would believe her innocence.

The vicar’s wife does not think the police will be able to solve the mystery and calls in an expert. That expert is, of course, Miss Marple. But we’re three-quarters through the book before Miss Marple arrives. If I hadn’t started the book already knowing it was a Miss Marple story, I would have assumed it was one of Christie's standalone mysteries, with the murder solved by Jerry and/or the police. But Jerry does provide valuable insights into the mystery. As an outsider, he sees people more clearly than a local would, and his comments help lead Miss Marple to the truth. Which of course she unearths, after only a few scenes of detection. While I like Miss Marple, I would have preferred it if she had appeared earlier and had a bigger role in the story, rather than just a cameo appearance. Or stayed away completely, and left it all to Jerry.

The mystery is very clever and the suspense is maintained until the end. I liked Miss Marple’s clever reasoning, even if it was largely based on assuming that everyone will behave in a stereotypical way. And I liked Jerry and Joanna, and their readiness to involve themselves in village life; a life that is obviously very different from the life they have each previously led in London.

There is one aspect of this story that is a little creepy from a modern perspective, and it’s one I've noticed in quite a few of Christie’s mysteries: the relationship between Jerry and a young girl from the village. Jerry is at least in his thirties. The girl, Megan, is almost twenty. There’s very much a hint of My Fair Lady to their relationship, as he unfavourably compares Megan’s appearance to that of his glamourous sister, then finally takes her to London for a complete makeover. Jerry tends to treat Megan more like a possession, or a loyal dog, than as an independent woman. But conversely, Megan is also shown to be independent, to have no wish to fall into the role expected of the daughter of the local solicitor, to engage in ‘proper’ womanly occupations. But apart from not fully appreciating the romance, I enjoyed this mystery. It’s a quick, light read, and a fun one.