For aficionados of the classic mystery, Magpie Murders is just glorious. Anthony Horowitz--he of Foyle's War, among other fine works--knows his stuff. He's aware of the limitations of the form, he respects them, he borrows respectfully, and he's a jolly decent writer. Magpie Murders, furthermore, is something of a tour de force, in that it presents not one but two interwoven puzzlers. There's nothing tongue-in-cheek about it, thank God, in spite of what a couple of seriously obtuse reviewers seem to have thought. It's catnip. It's the literary equivalent of an ice-cream sundae.
To say much more would be to spoil it. Just go read it, OK?