"Culture" is a pretty broad category, and one whose borders are porous. That's by design. Some might refer to some of these books as pop sociology, but to me that sounds pejorative. Culture books are close readings or explorations of subjects of mass or niche intertest or appeal, or studies of "other" ways of being that differ from the one we identify with. Sometimes business-esque books end up here, sometimes arty books end up here, and sometimes biographies end up here, but I think the thing that makes them hang together is their unique lens on our (or others') cultural situation. These are often some of my favorite books because I've always been a student of culture, both highbrow and low, and cultural studies was my graduate focus. Seeing how authors wrestle with these ideas is such an amazing treat.