It has 8.5 million microfilms and microfiches, more than 71,000 cubic feet (2,000 m3) of manuscripts, and close to 500,000 other materials, including motion pictures, DVDs, sound recordings, and computer files in its collections, in addition to extensive digital resources and the University Archives. It is the sixteenth largest library in North America, ranked by number of volumes held.

Initially, the system was a collection of 18,000 volumes stored in Morrill Hall. Daniel Willard Fiske, Cornell's first librarian, donated his entire estate to the university upon his death, as did President Andrew Dickson White. Under Fiske's direction, Cornell's library introduced a number of innovations, including allowing undergraduate students to browse through the books and check them out.

By 1885, the library had installed electric lights and stayed open 12 hours per day (instead of only a few hours per week—as most other libraries at American universities did at the time—just enough time for faculty to check out and return books), which allowed students to use it as a reference library.

According to wikipedia