Many of the major art databases index book reviews, namely Art Index, Bibliography of the History of Art, Avery Index to Architectural Periodicals, and ArtBibliographies Modern. CAA Reviews, an online-only publication of the College Art Association, includes reviews of art and architecture monographs, exhibitions, and essays organized by subject. The Art Libraries Society of North America publishes its art book reviews online: ARLIS/NA Reviews, plus see Recommended Blogs for Art Reviews (2008). Also, Bookforum reviews a good number of art books, with some reviews available at its website.
One can also search Articles+, do a search, entering as many keywords as you'd like contained in the book title in question, and select Book Review under Content Type on the left-hand side.
For canonical art historical titles, The Burlington Magazine has published a series of articles on important 20th-century texts in art history called Art History Reviewed. Just do a title search for Art History Reviewed in Art Index and you will see a listing of the specific articles and books reviewed. Burlington is available online in JSTOR, minus the last half a dozen or so years. Print issues are available in Marquand. Entries in this series have been compiled in The Books that Shaped Art History (Thames & Hudson, 2013), available in Marquand at N7480 .B66 2013.