The Clocks is an atypical Christie book. Although the blurb suggests that Hercule Poirot features heavily, he doesn't turn up till nearly halfway through the book! And even then he appears sporadically throughout, staying at his home while Colin Lamb (the main character) reports everything he sees and hears to the Belgian detective.
The murder occurs at the very start of the book and takes place in the cosy little street Wilbraham Crescent. Its certainly one of Christie's oddest murders: the body is surrounded by clocks, all reading 4:13, in the house of a blind woman who doesn't know the victim. In fact, no one claims to know the victim and all the leads seem to go nowhere. So Lamb (who was on the spot at the time) enlists his old friend Poirot.
The book doesn't suffer from Poirot's only fleeting appearances; its more fun without him, as he'd probably solve the murder with ease. Of course there are further murders as the book goes on, which make the whole thing more intriguing.
This book was published in 1963, in Christie's later years, when her books were being criticised for not being up to the standard of earlier ones. This one doesn't follow that pattern. Its a very clever mystery, as usual you're lead to suspect every character in the book, and you'll be kept guessing until the very end.
One of Christie's best.
Advantages: Clever plot, kept guessing throughout
Disadvantages: None that I can see :)