Like most of Mamet's books on film-making, this is very quick reading. You'll probably finish it in a sitting. And, like most of Mamet's books, you'll probably find yourself strongly agreeing with some of his insights and vehemently refuting the rest. He certainly doesn't hold anything back. "On Directing Film" is probably the least edgy of his books (of the ones I've read). It's also probably my favorite.