Hassan Hassan is a senior fellow at the Tahrir Institute for Middle East Policy. He is the co-author of “ISIS: Inside the Army of Terror,” a New York Times bestseller chosen as one of The Times of London’s Best Books of 2015 and The Wall Street Journal’s top 10 books on terrorism. He is a columnist at The National, an English daily in the United Arab Emirates, and his writing has appeared in The Guardian, Foreign Policy, Foreign Affairs and The New York Times, among others.