God I love a good puzzle book, I especially love a book that embodies the puzzle it is presenting, and tells its story through the mystifying and deceptive layers of the puzzle. This is one of those. Should have twigged it when I found myself amused by the way the audio book is a recording of someone reading transcripts of audio files, and in such a relatively flat voice, not even trying to add a bit o' cockney geezer, and dismissing it as the original book not necessarily being a neat fit for audio. Well, I was wrong, there's reasons and reasons and red herrings and herrings whose red washes off, this is excellent and delightful.