Mark J. Butler is Associate Professor and Coordinator of the Program in Music Theory and Cognition at Northwestern University. He is a music theorist whose research addresses popular music, rhythm, and technologically mediated performance. He is the author of Unlocking the Groove (Indiana, 2006) and the editor of Electronica, Dance, and Club Music (Ashgate, 2012). His most recent book project is based on extensive fieldwork with internationally active DJs and laptop musicians based in Berlin. By examining relationships between technology and improvisation, he reveals how these musicians create dynamic, novel performances through the transformation of seemingly “fixed” prerecorded objects.