Taken as a basic mystery, it's a decent light and fast read (very fast - I haven't seen type that large since 3rd grade). But if you're looking for the complex plotting, rich language, and wit of Dorothy L. Sayers, do not look here. It's also poorly edited - characters are in 2 places at once, one of Peter and Harriet's sons is simply missing, pilots "bale" out of airplanes, Walsh ignores the social structure of pre-War England - I could go on and on. Possibly the most interesting parts of the book deal with the living conditions in 1939 England.
Since Dorothy Sayers is dead, she's not going to write any more books, so lovers of the Lord Peter and Harriet Vane mysteries have to take what they can get. It was not bad, but Lord Peter doesn't appear very much in this book. Interesting if you like to read about what life in Britain was like during wartime.
If you love Harriet Vane/Wimsey, and want to keep on reading about her, I highly recommend this book. Ms. Walsh has captured the spirit of Sayer's heroine beautifully. It is also a good story about life in the British countryside during WWII.