From a quick Google search & a swift look at the subreddit book list; I've found Anthony Everitt's "Augustus: The Life of Rome's First Emperor" which seems fairly authoritative & certain about how Augustus laid the foundations for a great empire that would be remembered for years to come.

Some other books that might be of interest are: Ronald Syme's "The Roman Revolution". Which begins at the fall of the republic & the foundations of empire. The transformation of state and society, the violent transference of power and property, and the establishment of Augustus' rule

Adrian Goldsworthy's "Augustus: From Revolutionary to Emperor":

In the year 44 BC, when Julius Caesar was killed, Augustus was a mere teenager who had been adopted into Caesar's household. His reaction to Caesar's death was to step forward and proclaim himself Caesar's rightful successor. The Senate did not take him seriously, but over the following months he raised his own army and, after defeating Mark Antony in battle, became one of the three most powerful men in Rome. He was not yet 20 years old.

Over the next ten years he consolidated his power in Rome, and finally overthrew the last of his rivals in 31 BC. From that moment on Rome became an empire, and Augustus its first emperor.

Hopefully this has helped :)