"Too much traffic"
*sound of jaw hitting floor*
Judging from Levy's descriptions, Walker's library seems to give the Morgan Library a very serious run for its money. This now shares first place with Shigeru Ban's Library of a Poet on my list of all time awesome libraries. http://www.shigerubanarchitects.com/SBA_WORKS/SBA_PAPER/SBA_PAPER_3/SBA_paper_3.html