When Alfred Sloan and Charles Kettering, the geniuses of General Motors joined DuPont in the leaded gasoline business, they had loads of evidence leaded gas could kill.  The tobacco industry executives who worked to make cigarettes more addictive knew about the connections to lung cancer.  So, how could they do it? Barbara Freese tackles the question in her book Industrial-Strength Denial. How could anyone defend slavery or toxic mortgage packages?