So for ages, a regular Google search for a book author/title used to always give a books.google link at or near the top. I did it frequently to get citations. Now that link is nowhere in the search results (try it). Easy come, easy go - say your goodbyes to Google Books while you still can.
@philipncohen.com re: bye-bye google books, every few years I check whether they've updated the project history page ("after more than a decade..."): nope.