This is supposedly the more boring of the three books. Personally I found it the most satisfying and psychologically interesting.
The first book ends with Gandalf gone, lost in the depths of Moria. Pippin and Merry have been kidnapped. The book opens in a very dark place. Tolkien leaves for the last possible minute any hope that something good might happen.
A good chunk of the beginning of the Two Towers is about chasing down the Orcs that store the hobbits. It’s only when revealing that they survived furthers the story does Tolkien do so.
If the Hobbit is about greed, this book is about perseverance. Perseverance of Frodo despite the enormity of the burden. Perseverance of Eragron and the rest of the Fellowship party when all hope seems lost.
What is said to be the more boring part of the book — Frodo, Sam, and Gollum — has some of the more beautiful interactions and explores some of the more interesting character interactions there are in the books.