It may be hard to tell since I didn’t really review it, but I loved Anabasis enough that I was eager to read more from Xenophon right after finishing it. He’s one of the fortunate Classical authors to have had many of his works survive to the present day, so there’s plenty to choose from. His Socratic dialogues seemed like an obvious next step, but I’ve decided to put that on hold until I finish Plato’s.
When one begins a study of Western philosophy, especially with a focus on the history of philosophy, Plato is the most common starting-point. That’s reasonable enough, since he was, as far as I know, the first major philosopher from whom we have a lot of material, and so influential that Alfred North Whitehead famously commented that the rest of Western philosophy is “footnotes to Plato.”
However, there were several philosophers who do predate Plato.
Next to Aristotle’s Topics, The Histories may be the most vaguely titled book ever written. I suppose you can get away with that when you’re the Father of History, as Herodotus is called, and as the author of the first narrative history it’s not like there was much room for confusion at the time. Besides, while Herodotus makes the Greco-Persian Wars his ostensible subject, he’s so far-ranging that the broad title describes the work well enough.