Finding book reviews is *not* easy.
It's particularly difficult to find a VARIETY of reviews.
So, read this guide very carefully and thoroughly!
Reviews Come in Many Types
The earliest reviews will be the briefest and will be in publishing trade magazines like:
Close behind in time are longer and more substantial reviews in daily newspapers, weekly, biweekly, monthly or bimonthly popular magazine and journals of news and commentary like:
Last, but not least, are the scholarly reviews in specialized monthly and quarterly journals, like:
Consider Your Audience
The kinds of reviews you find will depend on the audience for the book:
Fiction or Popular Non-Fiction
Books that appeal to the broadest audience, the general public of strictly the USA Today and People Magazine crowd, will only be reviewed in popular magazines and newspapers.
Commentary/Opinion & Trade/Industry
Books that appeal to people who read journals of commentary/opinion will be reviewed in these types of journals. The same is true of trade/industry journals.
Scholarly books are reviewed in scholarly journals. There are even scholarly journals dedicated to just reviewing the literature of the field.