Suggest me a book or audiobook about the End of the Roman Republic

I’m interested in learning more about how the Roman Republic transitioned into the Roman Empire, and would like a non-fiction book on that subject.

Bonus points if you are aware of it being an audiobook on Audible, but not a deal breaker.

Edit: To add more context: The topic I am interested in is the situation of the Mediterranean at the time just before the first Triumvirate formed to just after Octavian was given the title Augustus. What caused the First Triumvirate, why was Cesar forced into war against Rome, how did Augustus get Cesar’s title and how did he succeed in Capturing Hellenic Egypt and what actually happened during the Pax Romana.