Crap is a fun and easy word to say. But what crap is is a lot harder to pin down. In Crap: A History of Cheap Stuff in America (University of Chicago Press), Wendy Woloson’s heavily researched book devoted to the many objects and ideas under that moniker, she does her level best to find a definition but doesn’t quite nail it down. But it’s not for lack of trying. Crap, it turns out, is an elusive target.