I picked up a copy of The Histories a couple months back and have spent as much time as I can soaking up the details of the Mediterranean world. I'm absolutely fascinated by the descriptions that Herodotus provides, even if some of them have been proven to be apocryphal. After a bit of inspiration I also picked up a copy of A General History of Pyrates, because it was written and published at about the same time as such figures actually existed.
I've really grown to appreciate the perspective of people who were alive and variously witnessed the things they're describing, rather than reading things written by a scholar in the modern era. I recognize that the older sources are potentially less reliable, but it's fun to read.
My question is, what other books such as the two I've mentioned are out there? I'm having a surprisingly hard time finding any booklists describing texts written by historians or biographers that were written at the same time as the subject material itself. I would greatly appreciate any leads.
It was common for historians in Antiquity, following in Herodotos' footsteps, to write about events in which they or their immediate ancestors were directly involved.
Thucydides wrote his History of the Peloponnesian War as it happened. The Athenians elected him general in 424 BC but he failed in his mission, leading to his exile. He lived long enough to see the end of the war in 404 BC, but not long enough to finish his account of it.
His contemporary Xenophon picked up where he left off and carried the historical narrative down to 362 BC in his Hellenika. This work contains much on the life and deeds of the Spartan king Agesilaos, who was a close friend of the author. Xenophon also wrote the Anabasis, an account of the March of the Ten Thousand, which is more directly autobiographical, featuring Xenophon himself as a prominent character.
Polybios and Tacitus are later ancient authors you might be interested in.
Xenophon's Anabasis and Ctesias' Persica both tell the story of the Achaemenid civil war between Artaxerxes II and Cyrus the Younger. Xenophon's is an autobiographical of his service as a mercenary fighting for Cyrus. Persica only exists in fragments, but there are collections compiled with commentary. Ctesias' writing covers all of Persian history, but includes the civil war when he was a physician in the court of Artaxerxes.
Livy's History of Rome is another one that covers a long span of time, but it goes up to events contemporary with Livy, including those that happened while he was still writing.
Sallust was roughly contemporary with the things he wrote about, at least in the "Bellum Catalinae". Caesar's Gallic and Civil Wars are naturally eye witness accounts, but need to be taken carefully considering he wrote them to secure his own reputation. For the later Roman period, the bits of Ammianus Marcellinus' history that survive are the years close to his own time, so that might be interesting for you too.
If you want to read something that isn't history or biography, I'd also recommend the letters and speeches of Cicero. They're very immediate, giving an intense insider's view of the fall of the Roman Republic (although obviously only from one, very particular perspective). On the letters at least, there are hundreds that have survived, and not all are worth reading, but there are several good selected translations out there, including the Penguins (https://www.penguin.co.uk/books/350/35094/selected-letters/9780140444582.html)