The annual Neural Information Processing Systems (NIPS) conference is the flagship meeting on neural computation and machine learning. It draws a diverse group of attendees--physicists, neuroscientists, mathematicians, statisticians, and computer scientists--interested in theoretical and applied aspects of modeling, simulating, and building neural-like or intelligent systems. The presentations are interdisciplinary, with contributions in algorithms, learning theory, cognitive science, neuroscience, brain imaging, vision, speech and signal processing, reinforcement learning, and applications. Only twenty-five percent of the papers submitted are accepted for presentation at NIPS, so the quality is exceptionally high. This volume contains the papers presented at the December 2006 meeting, held in Vancouver. Bernhard Scholkopf is Managing Director of the Max Planck Institute for Biological Cybernetics in Tubingen, Germany, Professor for Machine Learning at the Technical University of Berlin, and General Chair of the 2006 NIPS conference. John Platt is Manager of the Knowledge Tools group at Microsoft Research, and Program Chair of the 2006 NIPS conference. Thomas Hofmann is a Director of Engineering at Google's Engineering Center in Zurich, Adjunct Associate Professor of Computer Science at Brown University, and Publications Chair of the 2006 NIPS conference.