re: what do you think was lost in the burning of the library of Alexandria?

The library was burned or partially burned many times. But if you want to get a taste of what has been lost of ancient lit in general, just consider the fact that while we have only a handful of plays by Sophocles, we know he wrote more than 90 of them. Or you can consider that we are missing over half of one of the most famous works of history ever, Livy's History of Rome.

Most of the material that is left over we have because Christian and Muslim scholars thought it worth keeping for whatever reason.

But there were more libraries than Alexandria; I think the library at Pergamum was almost as big. Equally, and perhaps more disastrous, was the destruction of the library in Baghdad during the Mongol invasion.