Preface and Acknowledgments -- Contents -- I: Introduction and Overview -- II: Policies Driving the Expansion of Biofuel Production -- III: Next-Generation Technologies and Feedstocks -- IV: Dimensions of Sustainability and Expanding Biofuel Production -- V: Going Forward -- Appendixes -- Appendix A: Workshop Agenda -- Appendix B: Workshop Participants -- Appendix C: Description of Agency Activities on Biofuels and Sustainability -- Appendix D: Brief Survey of State Biofuel Policies in the Upper Midwest -- Appendix E: Assessing the Sustainability of Biofuels: Metrics, Models, and Tools for Evaluating the Impact of Biofuels -- Appendix F: Selected Bibliography -- Appendix G: Biographical Information: Workshop Participants -- Appendix H: Roundtable on Science and Technology for Sustainability.