ISIS, IS, the Islamic State. The name is chilling. The images are horrific. This is a group that beheads journalists—and yet one, the German Jürgen Todenhöfer, went out of his way to get an invitation to visit ISIS fighters in Mosul in 2014 to ask them to explain their beliefs. This book is the result of his conversation. My Journey into the Heart of Terror: Ten Days in the Islamic State shows how the organization grew from its al-Qaeda roots and takes a harsh look at the West’s role in its past and today. Along the way, Todenhöfer offers startling insights into what ISIS thinks, what it wants—and what must change if it is to be defeated. Only by understanding, Todenhöfer believes, can we move forward and combat ISIS’s radical, violent interpretation of Islam and the terror and destruction it brings.