Legislative mandates and incentives, volatility in oil prices and new research and technological advances are driving the expectation of major increases in the production of biofuels from cellulosic biomass. The term "sustainability" has been defined as the meeting of needs of present and future generations. Sustainable biofuel production is economically competitive, conserves the natural resource base and ensures social well-being. This book explores critical research areas and knowledge gaps relevant to the environmental, economic and social dimensions of biofuel sustainability. It also underscores the critical need for a common socioeconomic framework to develop a systems-level understanding for how these dimensions interact across different spatial scales, from the small plot or farm to regional to very large scales such as political, national and global scales.