This book has the makings of a fine Hollywood script. Start with Steve Bannon, the Harvard-educated former U.S. Navy officer, investment banker, and Breitbart News executive who became U.S. President Donald Trump’s alt-right political strategist. Fired within a year of the 2016 election, Bannon now promotes nationalist, far-right populists in Europe. Seeking to understand the roots of Bannon’s eccentric post-fascist beliefs, Teitelbaum (a music professor who also studies radical populists) convinced him to sit for 20 hours of interviews. Teitelbaum sets out to find the leaders of Bannon’s underground “spiritual school” committed to “Traditionalism,” a secretive ideology that rejects modernity, the Enlightenment, materialism, and globalization. They include a bearded supporter of Russian President Vladimir Putin who promotes “Eurasianism” as an alternative to the rotten West, the former leader of a Hungarian nationalist and anti-Roma party, an Iranian American author peddling plans for a eugenic purification of Persians, a Brazilian philosopher active on social media and close to Brazil’s current populist government, and a Briton with obscure corporate and political connections and the code name “Jellyfish.” Fun stuff—but in the end, the Traditionalists seem like cranks with obscure, inconsistent beliefs and only a small following.