We've arranged the resources into two categories: Popular and Scholarly.
In general, if you think that the average person would read the book for pleasure, try the Popular resources.
If not, try the Scholarly resources.
There can be some overlap between these two categories, so try searching in both types of resources if you're unsure which category your book falls into.
A good place to start would be the Research Guide whose subject is closest to the book's, linked below.
If your book is not related to a specific subject area or you aren't sure which subject to search, try one of the general databases below.