To find book reviews, you'll need to know the title and author of the book. Knowing the date it was first published is also very important, because most reviews are published shortly after the book.
Library databases that provide access to historic newspapers and magazines will be a good place to start looking for 18th, 19th, and early 20th century works. For more recent books, choose databases that provide access to contemporary journals and newspapers will be more helpful. There are also several social social networking sites that specialise in book reviews by members.
Library databases to search for reviews, organised into Historic and Current.
If you're looking for reviews of a specific book, the best way to them is to search these databases for the Book Title and/or Author, and look for a way to limit your results to Book Reviews (Note: reviews are not always classified separately from articles).
These print and online magazines and newspapers all contain reviews of Books.