What is the main conflict in Freakonomics by Steven Levitt?

This is a nonfiction book that explores links in the economic world raether than a narrative conflict. What trait is shared by both Ku Klux Klan members and real-estate agents? In what way do the working worlds of Chicago schoolteachers and Japanese sumo wrestlers intersect? These questions might seem puzzling at first glance, but the answers provided in Freakonomics: A Rogue Economist Explores the Hidden Side of Everything reveal that fundamental notions of economics can be used to interpret just about everything in modern society.