I read this literary classic way back in middle school, and promptly forgot everything about it. I see why this is recommended for precocious younger readers, but I think it takes an adult mindset to understand what White is actually writing about. There's an awful lot of philosophizing in this book that surely went right over my head, even as a bookish seventh grader, though the humorous writing, the humanity of the characters, and the rollicking quests are classic young adult fodder. So it must be concluded that "The Once and Future King" is a complicated book, for complicated souls. It was daring, really, to write a book about King Arthur, renowned for jousts and chivalry and a generally violence-centric society (even if "he" did try to create a more civilized rule of law) and then so clearly turn it into a paean to - and plea for - pacifism. Arthur's thoughts are surely White's own: there is no excuse for war, no excuse for killing another. One wrongful death leads to another, and another, until the world is swimming in blood and there's no telling whether you have more blood on your own hands or your enemy on his.
The writing is quite different throughout the four sections of the book. It starts out quite humorously, then becomes more serious as the book continues. The inner sections are a bit difficult to plow through, while the last hundred pages or so are downright riveting. This will surely be a classic for a long time to come.