One of the things people don't necessarily keep in mind is that there is a great big unknown here -- how much did NOT survive. Herodotus' work survived, while Hecaetaeus' slightly earlier (and somewhat similar) history did not. The prolific and erudite and extremely old Michael Grant claims that the works that didn't survive were not much good, and were not preserved for that reason. His claim is entirely without foundation, for obvious reasons (we can't read the stuff and find out). There are works which people wish we had simply by virtue of fragments which have survived as quotes in other ancient works.
Fascinating history of the library. Notes that the library was *not* burned by Julius Caesar, and in fact was around during Roman times, and was finally consigned to the flames by the Moslems: