A book review usually appears in a magazine or journal soon after the publication of a book; reprints, later editions and reissues are often not reivewed, so it's important to have the original publication date. For electronic sources, a keyword search on a word from the title or author’s name (plus the word review) is often sufficient.
Note for literature students: while reviewers are referred to as critics, reviews have a different purpose from literary criticism. Ask a reference librarian for good sources of literary criticism, as well as for reviews.
To find book review sources in SOUTHcat, try a keyword search on "book reviews".