Suggested by Prairie Progressive:
Do you read the inside flaps that describe a book before or while reading it?
You mean the blurb? Doesn’t everyone? (Judging by some of the other responses, apparently not.) I always read it before reading the book; if I’m browsing at a library or book sale, the back cover (or inside flap) is how I determine whether or not to read a particular book. A tempting blurb can induce me to read a book I’ve never heard of.
In fact, I can’t imagine reading a book without reading the cover first! Perhaps that would be an interesting library experiment to try: ignore the blurb and dive in unprepared.