This book contains a variety of research related to the future of the federal budget. Significant uncertainty surrounds long-term fiscal projections, but under any plausible scenario, the federal budget is on an unsustainable path- that is, federal debt will grow much faster than the economy over the long run. In the absence of significant changes in policy, rising costs for health care and the ageing of the U.S. population will cause federal spending to grow rapidly. If federal revenues as a share of gross domestic product (GDP) remain at their current level, that rise in spending will eventually cause future budget deficits to become unsustainable. To prevent deficits from growing to levels that could impose substantial costs on the economy, this book examines the revenues that must rise as a share of GDP, or the projected spending that must fall -- or some combination of the two which must be achieved. This book consists of public domain documents which have been located, gathered, combined, reformatted, and enhanced with a subject index, selectively edited and bound to provide easy access.