Allen W. Wood is Ruth Norman Halls Professor at Indiana University and Ward W. and Priscilla B. Woods Professor Emeritus at Stanford University, California. His recent book publications include Karl Marx (2004) and Kantian Ethics (Cambridge, 2008). He has also edited and translated numerous works of philosophy and published extensively in academic journals. Songsuk Susan Hahn is Assistant Professor of Philosophy at the Université Concordia in Montréal, Québec, Canada. She has also held teaching appointments at The Johns Hopkins University, Harvard University, Massachusetts and The American University of Paris, France. She is the author of Contradiction in Motion: Hegel's Organic Concept of Life and Value (2007).