My favourite Christie BOOK is the only one she published under her second married name, Agatha Christie Mallowan: Come, Tell Me How You Live... -It's basically just a description of what it was like when she went with Mr. Mallowan on the excavations in the Middle East, and it's a really good read. Her prose even seems more lucid and eloquent when she's not doing the who-dunnits. I bought it after they had that exhinbition about her at the British Museum a few years back, and it is still one of the best pieces of autobiography that I can think of.