Third book in the Adam Dalgliesh series. Dalgliesh needs a break, partly to recover from his last case and partly to think over his relationship with Deborah Riscoe. As is his habit, he goes to stay for a few days with his Aunt Jane, who lives in a small, remote coastal settlement populated mostly by writers. Naturally, he finds murder even in Monksmere.
In this case, Dalgliesh is not only not the investigating officer, but not officially involved in the case other than as a witness and relative/aquaintance of the suspects. But as someone with inside knowledge of the community and a direct connection, he can't but help but be involved with the local police as they attempt to solve the case.
It's all too clear that the only plausible suspects are the inhabitants of Monksmere, but that doesn't stop them trying to find some way to first deny that there has been a murder, and then that it is one of their number who was responsible. James carefully shows the differing and often eccentric personalities, the ways in which they manage to live in a sometimes uneasy tolerance of each other in a very small community, and the effect the murder has upon those relationships. With the victim being a writer of detective stories, and all the suspects being writers, there are multiple levels of meta going on.
I found the book an enjoyable read, though flawed in places. But it's far from her best work, and even if you don't like this one it would be worth trying one of the later books. It's also worth bearing in mind that the book was written in 1967, and social changes since then could make the book feel dated and implausible if you're not aware of this.
Unnatural Causes
at Amazon UK
at PlayUnnatural Causes (Adam Dagliesh Mystery Series #3)
at Amazon US
at Powell'sLibraryThing entryAlso available in audiobook format at audio.com