Full-text archive of core journals in select disciplines, going back to the first issue of each title. Allows powerful searching across fields. Jourrnal issues from the most recent 3-5 years are usually not available electronically through JSTOR, but Princeton will have another form of access.
If you do not find a review in one of these databases, confer with a reference librarian about other approaches, depending on the date and subject of the book in question.
Using Google Scholar can be a fast way to find an article for which you know the title. However, you may be overwhelmed by search results while in the exploratory stage of research. Note that not all the library's articles will be discoverable by Google Scholar.