In this book we introduce the basics of the federal budget process, provide an historical background on the foundation and development of the budget process, indicate how defense spending may be measured and how it impacts the economy, describe and analyze how Planning, Programming, Budgeting, and Execution System (PPBES) operates and should function to produce the annual defense budget proposal to Congress, analyze the role of Congress in debating and deciding on defense appropriations and the politics of the budgetary process including the use of supplemental appropriations to fund national defense, analyze budget execution dynamics, identify the principal participants in the defense budget process in the Pentagon and military commands, assess federal and Department of Defense (DoD) financial management and business process challenges and issues, and describe the processes used to resource acquisition of defense war fighting assets, including reforms in acquisition and linkages between PPBES and the defense acquisition process.