I'm not sure I need to review this extensively, because many have. I just want to say: I read this with a horrified fascination. Read it only if you have a strong stomach (or, at least, not a weak one). Because it is the ugliest, most nihilistic novel I've ever read. If Satan were a book, he would be The Chocolate War.
Actually, the most disturbing thing about this book is that I first saw it on a teacher's bookshelf. When I was in grade school, no higher than fourth grade. Fortunately, I didn't try to read it then--I was just curious about the title. (I wondered what chocolate would have to do with a war.)
There is a sequel, Beyond the Chocolate War, but all it does is tie up loose ends, and is less worth your time.
At least one reviewer calls it a book about good and evil, and I wanted to say that was wrong--there is NO good in this book--but I was forgetting that there are a few clearly good characters. (I'm not sure Jerry is one. I think he rebels against the school without understanding why, that he feels an instinct to buck the system.) The clearly good major characters are Brother Jacques and Roland Goubert--that's about it. Ugly school, ugly world.