Because The Two Towers is the central portion of a longer work, its structure differs from that of a conventional novel. It begins and ends abruptly, without introduction to the characters, explanations of major plot elements, or a strict conclusion. This is characteristic of the technical classification novel sequence, not a book series — though it and the other two volumes are not individual novels themselves.
The first section follows the divergent paths of several important figures from The Fellowship of the Ring, but tells nothing of its central character, on whose fate so much depends, enabling the reader to share in the suspense and uncertainty of the characters. The narrative of the second part returns to Frodo's quest to destroy the evil that threatens the world.