Did you ever see the movie by Steven Spielberg? It was Christian Bale's debut. Anyway, this is the book that movie is based on.
Empire of the Sun by J. G. Ballard. It's about a British boy separated from his parents during the Japanese invasion of Shanghai. He is put into a prisoner camp and the book recounts his time during the war. Supposedly, the book is a novel but based on Ballard's real life memories. It's a very gritty, graphic book but fascinating in its own way. The movie version is really good too.