Protagoras, Democritus, and Prodicus (the last of which I had never heard of before, but was apparently famous for his comparative atheism) are produced as examples, but never quite come together as genuine examples of what we might consider atheists.
The book is fascinating, but not a small amount of it feels like fascinating filler. I loved reading about who was at Callias house to hear Protagoras speak and the intellectual foment of Periclean Athens, but joy does not a hypothesis prove.
It seems less a history of atheism, despite the author’s valiant efforts, than is is a book illustrating that religion and religious belief in the classical period of the Mediterranean was more complex than it is given credit for. And I was frequently reminded with Sir Roger Scruton’s tendency, when speaking of religion, to go reference the Roman household gods as things that were honored, without necessarily being deeply believed in.
But even in that argument, one can reply that it is limited in the sense that this is elite history; in fact, it is a history of philosophers. Even if you believe he has proved the existence of something like modern atheism in classical Athens or imperial Rome, he has not proved that it was widespread or even that it existed beyond Cicero’s dinner parties.
But it’s fun to read about Cicero’s dinner parties and the many, mostly non-Plato/Aristotle/Socrates philosophers of that ancient time and worth spending a little time with them, even if no important points about atheism were actually made.