That's by far his weakest book tbh though it's entertaining. Like he's basically winging it/being very superficial with what he thinks Roman social relations were in a way that doesn't line up with what he cites (which was already pretty old in some cases when he cited it and wasn't up to date) and it leads to a big speculative hunch that I found super unsatisfying. Like It's a super fun theory to have about Caesar, but not one I think there's much evidence for and there's scholarly reasons you don't see it crop up in Roman studies journals. For being a historical materialist, Parenti never really engaged much in historical methodology (makes sense though, he was a political science researcher first then branched out in a sort of pop history by an academic that we see a lot of but for socialists instead of libs)

I have heard some stuff he winged kind of ended up being shown in Mass Oratory and Political Power in the Late Roman Republic by Morstein-Marx, but it's a complete coincidence if that's true lol.