I think A Caribbean Mystery, originally published in 1964, is one of the best of the later Miss Marple books that Agatha Christie wrote in the 1950s and 1960s. But if you are a fan of Miss Marple, be sure not to overlook one of the earliest books to feature her, 1942's The Body in the Library. It was the second Miss Marple book. The concept of a strange body found in a person's library had become something of a cliche - a fact that Christie knew quite well, as she deliberately placed the mysterious body of an unknown woman in Colonel Bantry's library. Bodies are always being found in libraries in books, the colonel says – I’ve never known a case in real life. Perhaps you will now, says Mrs. Bantry.
I reviewed The Body in the Library here a few years back; if you want to hear the audio review from the podcast, you can click here to listen to it. If you haven't read it - well, it's one of the best Miss Marple books, and I commend it to you highly.