There are several places to find book reviews, here are a few suggestions-
Search the databases by type and you will find a book reviews section in the pull down menu. That list of databases is available here See especially Book Review Index (1965-date) and Book Review Digest Plus (1983-date)
America: History & Life database contains book reviews written since 1964
JSTOR database has full text book reviews going back to the late 19th century in some of the journals included there.
Limiting document types to book reviews is a search option in both these databases.
Combined retrospective index to book reviews in scholarly journals, 1886-1974 This set is in the reference collection on the main floor.
combined retrospective index set to journals in history, 1838-1974 This set is also in the reference collection on the main floor