Recently, The Metropolitan Museum of Art in New York has released 643 art and art history books online, in full color, available for free. Highlights of this release include the fact that over 300 of the titles are out-of-print, (and therefore hard-to-find) originally published between 1968 and the present.
The database, called MetPublications, allows users to search and read publications online, but can also be downloaded as a PDF for no extra cost. For out-of-print titles, MetPublications also offers a print-on-demand feature for 140 different titles. Newer titles that are currently in print can be previewed online, but are not yet fully available for free online.
Titles that are free to read online are available through Google books, for example, this digitized version of Portraits by Ingres: Image of an Epoch (published 2000). I personally prefer to download the full PDF, as I find the Google book viewer to be somewhat distracting–especially considering that a main feature of these books is their stunning, full color reproductions.
On the site, a toolbar helps sort the vast quantity of titles available, allowing you to access for example, only the titles with the full text available online, notable publications, or popular Met titles. The user-friendly website is perfect for scholars looking for research material and art enthusiasts alike.
This move to open access also speaks volumes in regards to the popularization of digital publishing within the field of art, as the Met is following the trend of other museums. For example, The J. Paul Getty Museum, who in 2014 released over 250+ art and history titles online for free the to the public, available on their virtual library.