Super book and a well-crafted Margery Allingham, although there are some bits that don't come together well (or make sense), such as where Albert Campion meets his old friend Stanislaus at the very start of the book at an out of the way, little known rendezvous point purely by accident. All very contrived -this introduction to the story could have been done a lot more concisely and in a much more interesting way.
All said, it's a great story, and the reason why I like it is because it's quite a tense and in places claustrophobic rendition of a family imploding based on years of tension, dislike and plain hostility towards one another. We get a picture of the results of that "poison" all coming out in the wash and it makes for an exciting read.
I did start to guess what was going on towards the end of the book, but it was still not clear how the murderer had done it, so it was still very worthwhile reading to the end to find out. In fact, I was waiting for some more deaths to occur since the culprit seemed to have planned quite far ahead and with some ingenuity! But then Allingham didn't really write stories about mass-murderers, so it was probably best she stopped there!
About Campion - Margery Allingham has again written all the way through this book that Campion comes across as vacant, slightly imbecilic and perhaps a touch daft to other characters in the story, but I have to say he comes across as anything but to me. In fact, he's one of the more interesting and on-the-ball detectives from classic detective story fiction and his switched-on attitude means he doesn't really ever disappoint; even if his friends get annoyed with him not disclosing his secret knowledge to them (I'm referring here to the fact that Stanislaus gives Campion the cold shoulder for a couple of days in this story when he can't work out what Campion is obscurely hinting at).
Give this book a go - I'm sure you'll like it, and remember - be very careful to be nice to the rest of your family, particularly if they live with you...