According to Marshall McLuhan, if you turn to page 69 of any book, read it and like the page, you should buy the book. The Page 69 Test has been testing that theory for the past 14 years with thousands of books analysed. I might have to try this out the next time I’m in a bookshop (sometime in 2022 no doubt).
See also: The Page 99 Test, following a similar Ford Madox Ford saying—”open the book to page ninety-nine and read, and the quality of the whole will be revealed to you.”