Book reviews are short articles that can tell you about the contents and scope of a book.
They are published in peer-reviewed topical journals, popular newspapers and magazines, and in publications that only contain reviews.
Full Text Reviews
Reviews in Newspapers
Citations & Abstracts of Reviews
SuperSearch is a great place to start for journal articles, books and almost everything else the library has, in one easy to use interface.
For searching with more focus and precision, try one of the databases recommended on this guide.