Who are the authors: are they researchers or university tutors or experienced professionals/practitioners? Does the book have endorsements from other researchers?
For whom it is written: various books are written for different audiences, e.g. general public, undergraduate or postgraduate students, specialists in a particular subject.
Who is the publisher: have they published other academic titles? If the publisher is obscure or unknown to you, check again for reputable author and endorsements.
When was the book published: some titles in Google Books are not the latest editions.