Book reviews can save you time- they provide short critiques and responses to a book's thesis, analysis and structure. They can also illuminate previous scholarship and highlight current debates in the field.
Here's an example of a book review from JSTOR.
Books (whether printed or online) are still a crucial component of scholarly discourse, especially in the humanities and social sciences.
Finding book reviews can be very simple. It can also be very difficult. Ask a librarian for assistance if you do not have success relatively quickly.