To begin a book is to perform a paradoxical act. There is always a lead-up to the beginning, a history before the history of the start. This book, for example, grew out of my experiences with problems and puzzles in international law over the past few years – or longer. It began when I first looked up the text of a Security Council resolution. I expected to find decisions and recommendations, in line with the formal powers and mandate of the Council. And indeed, I found all of these things. However, I was most of all struck by something else: the lengthy preamble of the resolution, which extensively recalled, reiterated, reaffirmed and recognized previous resolutions. What was going on here? What does it mean to begin a resolution by calling upon the past, by reaffirming and recognizing your own previous work? This book began when I was coach of a team of students for an international moot court competition. I had been coaching and supervising moot court teams for a couple of years and, while I truly enjoyed the experience, there was also always a yawning uneasiness about it. During the competition there was little to no room for the critical and reflexive attitude that I try to foster in the rest of my teaching. Instead, I largely followed the format of the competition during the preparatory sessions, mostly focusing on the strategic use of international law in order to win a case. Increasingly, I started to wonder whether there might be different, more reflexive and experimental ways to rehearse international law. This book began when I first saw Rithy Panh’s documentary films on the atrocities committed by the Khmer Rouge. I was especially moved by the reenactments of traumatic experiences that were shown on screen. Watching these reenactments gave me a different sense of one of the core concepts of the Statute of the International Criminal Court: “unimaginable atrocities.” Panh’s films made me wonder whether the pictured reenactments might have something important to say about that which the International Criminal Court labels as “unimaginable” and others as “unspeakable.”