The second volume of The Lord of the Rings continues Frodo Baggins' journey towards the dark land of Mordor while the rest of his companions deal with armies of the Great Eye and the traitorous Saruman. 'The Two Towers' is where J.R.R. Tolkien showed the reader the danger his world was in and raising the stakes by showing the effects of Sauron's darkness was already having on lands he had captured.
'The Two Towers' contains the third and fourth books that Tolkien divided The Lord of the Rings into. The third book begins with Company, sans Frodo and Sam, battling the machinations of Isengard in various ways. The fourth follows Frodo and Sam from their split from the Company to the very edge of Mordor itself thanks to Gollum. Throughout Towers, Tolkien continually builds the tension and the stakes all the characters deal with as the darkness threatening their world goes on the move. Although he separated the two story arcs into different books, Tolkien drops hints to his overall timeline by the flight of the Nazgul that all the characters see at various times. Unfortunately Tolkien's decision to split the story arc of the rest of the Company into two created the need for a flashback retelling of the Ent march against Isengard instead of a 'first-hand' account of the battle.
Although the material in Towers was originally intended by J.R.R. Tolkien to be directly in the middle of an entire one-volume story, a publisher decision to split the tale into three volumes creating mixed results for Towers. As intended by Tolkien the material increased the tension and action the characters experienced, only to suddenly cut off as events seemed to be gaining traction. However, the cliff hanger quality that Tolkien intended at the end of Book Four as it finishes Towers is retaining making the reader want to see what happens next in the story of Frodo and Sam.
'The Two Towers' reads like it was intended, the middle part of one-continuous story, resulting in it never really feels like a individual book. In Towers, the characters introduced in Fellowship continued to grow and start interacting with various new characters stepping onto the stage of the story. Along with character development, the increasing action and rising tensions between good and evil build up the overall story of The Lord of the Rings. Upon finishing The Two Towers, readers can not wait to see how Tolkien's epic is completed in 'The Return of the King'.