This is the third Adam Dalgleish book, and was a library check out for me. I decided to revisit P.D. James this year as part of my "Century of Women" project. Unnatural Causes is the third in the series, and was published in 1967.
This is my favorite book so far because it was so cleverly plotted. The victim is a mystery writer, and is found in circumstances that feel like something out of his next planned book. Well after his death, an envelope containing the typed opening of his next book is received, and it echoes the circumstances in which his body was found, and was obviously typed on the victim's own typewriter.
Adam Dalgleish is is involved because he has gone to Suffolk to visit his aunt, a respected amateur ornithologist, lifelong spinster, and extremely self-contained woman. The victim was one of her neighbors, and her small circle of neighbors all have a motive to murder. Dalgleish is also trying to decide what to do about his romantic relationship, which has reached a critical juncture and he must decide if he is going to ask the woman to marry him or end the relationship all together. Aunt Jane lives in an isolated cottage on the Suffolk coast, so there is a lot of discussion about remote coastal landscapes that look something like this:
As an aside, this book would work brilliantly for the "dark and stormy night" space in Halloween Bingo, as there is a confrontation that occurs in a flooded house during a devastating coastal storm.
The way that the solution to the mystery is presented isn't completely successful, in my opinion. The end of the book is basically a transcription of a long, somewhat rambling, recorded confession left behind by the murderer. This type of device has a tendency to drag on, and it does so here, but it's a relatively small quibble. Otherwise, the book is extremely cleverly done, and the meta elements are a lot of fun.