The Iran-Iraq Warby Pierre Razoux is what I'd probably recommend. The simple fact is that there aren't that many in-depth treatments out there, so you don't have too many options to choose from anyways, but it is a generally well reviewed book, and despite its flaws (uncritical repetition of the 'Keys of Heaven' story, which at the least needs analysis given the controversy, for instance), you aren't going to find a much more thorough academic treatment out there.