I found this at a yard sale many years ago and thought the cover was just wonderful (if not coffee stained). The ironically named Ruth Belov Gross writes all about your skeleton with fun lines like, “If you didn’t have any bones, you would flop around like spaghetti.” It’s got some great artwork inside that has that sort of South Park construction paper cut out look to it. It’s long out of print, but you can find a few copies on Amazon for less than 2 bucks.