Novelization
The novelization of the film was written by Matthew Stover. It includes much more dialogue than the film, including a conversation between Count Dooku and Darth Sidious, where the reader learns Palpatine lied to Dooku about what the Empire would truly be; and a conversation between Mace Windu and Obi-Wan Kenobi where Kenobi expresses self-doubt about whether he is the right Jedi to battle General Grievous, only to be told by Windu that while many consider him (Windu) to be a master-swordsman due to his creation of the Vaapad fighting style, but that he considers Kenobi the superior swordsman in that he took an existing style (Soresu) and mastered it to the highest degree. The novel includes many minor details. For example, during the Battle of Coruscant, Anakin's callsign is Red 5, a reference to Luke's callsign in the climactic battle of A New Hope, and one of the Republic capital ships is commanded by Lieutenant Commander Lorth Needa, who becomes Captain Needa in The Empire Strikes Back. There are also references to the Star Wars: Republic comic book series, such as the Battle of Jabiim (Volume 3). In addition to this, the siege of the Jedi Temple is much more violent and far more graphically explained than the cinematic version.
Some unseen or unheard-of elements to the Revenge of the Sith story were fleshed out in the course of the novel. Such examples include more discussions between Anakin and Palpatine, in which Palpatine explicitly says that Darth Plagueis was his master; in the film, it is merely hinted at. Not only is Saesee Tiin revealed to be a telepath, but his horn, lost in the Clone Wars, is revealed to have grown back. These are a few examples of many descriptions of characters' feelings and inner narrative. There are even some humorous lines added in, including extra dialogue in the battle between Grievous and Obi Wan — Grievous says that he was trained by Count Dooku, and Obi-Wan replies, "What a coincidence; I trained the man who killed him".
Read more about this topic: Star Wars Episode III: Revenge Of The Sith