Scholarly reviews are found in peer-reviewed academic journals. These tend to be longer reviews that are written by an expert. In library databases, you can often limit your search to "scholarly", "peer-reviewed", "academic" or "refereed" journals. These will likely be published within three years from the first date of publication, though new reviews might be published for new editions.
Databases best for finding Scholarly Reviews include:
Popular reviews are found in newspapers and magazines. They are usually shorter and may not be written by an expert on the subject. These usually come out within a year of when the book (or a new edition) is published.
Databases best for finding Popular Reviews include:
Many databases in your subject area will contain book reviews. You can try doing a search for the book's title or the title with the addition of the word "review."
To find scholarly reviews: limit your search to "scholarly", "peer-reviewed", "academic" or "refereed" journals.