The holdings of the ancient library in Alexandria, Egypt, were enough to send any bibliophile into orbit — until it went up in flames in 48 b.c. The original texts may be gone, but at last there's a Bibliotheca Alexandrina that might equal the old. Designed by Sn¿hetta, a youthful Norwegian firm, and 10 years in the making, it is as much a monument as a place of study. In a nod to the information age, the circular roof resembles a microchip. Inside, the reading room seats 2,000. (A pedestrian bridge links the library to a new science center and planetarium — Alexandria is, after all, where Aristarchus first determined that the earth revolved around the sun.) But with only 500,000 books in the collection, how are they going to fill the shelves?Major libraries are sending copies of their most important works, just as they did after the library burned two millennia ago. On the Corniche at Port Said St.