And besides, Suetonius had access to Augustus' personal correspondence and so had a better glimpse into the character of the man himself -- habitual grammatical lapses and all -- than we do. His vices and eccentricities are here along with his virtues. So where is the coherent coverage of the civil wars? It may simply have been a casualty of Suetonius' "grammatical" biographical approach, which organizes its material along thematic and not chronological lines and so can mislead modern readers looking for a more straightforward year-to-year narrative. Significantly, the wars are the first of the "subject headings" (49) into which Suetonius dissects Augustus and his imperial career, and thus arguably the most important. It is only by accident that this section of the text follows immediately on the prefatory discussion of Augustus' upbringing and early career, just as it would in a chronological narrative. After this, it is easy for the casual reader...

Unlike any of the Twelve Caesars to come (much less their predecessors), Augustus is unique in needing to establish the basic forms of imperial power and succession, but again, Suetonius' approach is not especially well suited to analyzing this evolution from triumvir to emperor in a way that casual readers will find informative. Ultimately, Suetonius is interested in depicting good and bad men and how they wield power, and only secondarily in pondering the apparatus of imperium itself.
Works Cited

Suetonius. The Twelve Caesars. Trans. Robert Graves. New York: Penguin, 1979. Print.