The Metropolitan Museum of Art has launched MetPublications, a portal that will "eventually offer access to nearly all books, Bulletins, and Journals" published by the Met since 1870."
MetPublications now makes available 370 out-of-print titles, including lots of informative and visually-packed art catalogs from the museum's past exhibitions. You can read the books online or download them in PDF format (although I should warn you that the PDF downloads take some time, so be patient).
http://www.metmuseum.org/research/metpublications
Their website was down earlier this week because of the storm, but it seems to be back up now.