I finished Two Towers last night in a dead sprint to the end. Not very many books drive me on to the end like this one did. I loved the book, though I hadn't been sure beforehand that I would. When I read Fellowship last year, it didn't have the same effect. Two Towers seemed surer, somehow, in large part because of the way Tolkien develops Frodo, Sam, and Gollum. They are distinct in subtle ways, but they are also very complex characters. Gollum is not all bad; he's bad and good in ways that are at first difficult to recognize as such. Sam has his own "Gollum" moments of behavior, and refuses to see any possible good in Gollum. You might have just read that and said to yourself, "by the end Sam seems to have been right about Gollum." True in one way, but the beauty of the novel comes, in part, from the way Tolkien makes Gollum a character for whom we can feel moments of hope. What he winds up doing matters in some ways less than the way that Frodo draws the Smeagol side of good out of Gollum, even if only temporarily. I didn't expect to be moved at the end of the novel, but that's what I experienced.
Many, many people have said that Lord of the Rings is the highwater mark for fantasy writing. I saw that clearly for the first time in Two Towers. I've felt several times in reading fantasy novels as if I was standing on the edge of someone's imagined world, but never really able to enter it. In TT, I fell into the world Tolkien describes many times.
I have not seen any of the Lord of the Rings movies, so the world I've imagined comes out of my head, not images someone else created. I certainly don't plan to see any of them until at least after I finish Return. I like this book enough, however, that I'm not sure I want to have the movie version compete with what I've experienced in my reading of the novel. I don't think that often, so it's an indication of how much I enjoyed the novel, and likely will in later readings of it.