Alexandria library

The myth goes that there were great secrets within the Alexandrian Library. It seems we all forgot one critical thing: Everything within the walls of the Library was copied from other sources. Everything. When the library was founded during third century BC by the Ptolemy's, it was part of their taxation strategy, or more precisely a "toll road". Everyone who wanted to reach beyond Egypt to the Red Sea, or the other way around to the Mediterranean ships docking in Egypt, with people wanting to pass through, well, they had to hand over everything written onboard for copying by Alexandrian scholars and writers. Maps, logs, literature, diaries and so on, and everything were gathered in the Library of Alexandria.
I am intrigued by the library of Alexandria because of the vast amount of ancient knowledge that was apparently kept there. I am not really looking for any secrets myself, but could you imagine what could be learned from a database of the world’s history.

Did the Alexandria library hold lost secrets?