Justin E. H. Smith is Associate Professor of Philosophy at Concordia University in Montreal, Canada. He is the author of Divine Machines: Leibniz and the Sciences of Life (Princeton University Press, 2010). In 2011 he will be a member of the School of Historical Studies at the Institute for Advanced Study, Princeton. Ohad Nachtomy is Associate Professor of Philosophy at Fordham University. He is the author of Possibility, Agency, and Individuality in Leibniz's Metaphysics (Springer, 2007).