There's a series of three books that you have to read, that are almost like the twilight of the republic, rise of the Empire
Labyrinth of Evil
Takes place immediately before the events of Revenge of the Sith, and is the story of the Jedi trying to track down Darth Sidious. On Coruscant Mace Windu leads a search through the undercity tracking clues to who Sidious is. Meanwhile Obi-Wan and Anakin pursue their own search for the identity of Sidious and this leads them into a confrontation with Dooku. Meanwhile Sidious continues to manipulate the republic and choke off freedoms in the republic in the Senate. A great well written book
https://www.amazon.ca/Labyrinth-Evil...1515672&sr=8-1
Revenge of the Sith
https://www.amazon.ca/Revenge-Sith-S...1515563&sr=8-1
Dark Lord rise of Darth Vader
Starts at the end of the Clone Wars and the betrayal of the Jedi by the Clones as it follows two Jedi who narrowly escape the Clones. Meanwhile it shows the trial of Anakin as he transitions into Vader and faces his choices. We also get to see how much of a real bastard Palpatine is. Especially in a throne room encounter with Bail Organa Mon Mothma and other senators.
https://www.amazon.ca/DARK-LORD-RISE...1515857&sr=8-2
If you look on Amazon there's a one book set that is all three novels and its a great deal.
https://www.amazon.ca/Dark-Lord-Tril...1516006&sr=8-1