Fans of Austrian economics know hedge fund manager Mark Spitznagel as a brilliant thinker thoroughly steeped in Menger, Böhm-Bawerk, Mises, and Rothbard. His excellent 2013 book The Dao of Capital was rooted in Austrian capital theory and "roundaboutness," and his application of of that theory has proven highly beneficial for his investors. Now Spitznagel is…