America has a fundamental misunderstanding of what drives violence, and that’s gotten in the way of doing more to prevent shootings. That’s the premise of the new book “Unforgiving Places” by University of Chicago Crime Lab director Jens Ludwig. Ludwig, an economist, talked about that in an interview with the Chicago Sun-Times that has been edited for length and clarity. Sun-Times: We are at a location you return to several times in the book. Tell us about it.