In ancient times, the library of Alexandria was considered to be the biggest in the world. All businessmen landing their goods in the harbor of Alexandria were required to deposit any book scrolls in this library, where they were copied before being returned. Unfortunately, this library was completely destroyed by fire.
The Library of Alexander is believed to have been founded by Demetrius of Phaleron at the behest of Ptolemy I. Demetrius had been a student of Aristotle, a ruler of Athens who was later forced into exile after the death of Alexander the Great. He accepted a position in Egypt as a tutor to Ptolemy's children, and from that position worked to shift Aristotle's legacy to Alexandria. It has been widely assumed that this was done via the purchase of Aristotle's personal library, then the largest in the world, shortly after that philosopher's death in 322 BC.
The history of the Library over the next few centuries can be seen as an extension of the scholarship and research methodology established by Aristotle in Athens.