The Administration requested $523.9 billion to cover the FY2017 discretionary base budget of the Department of Defense (DOD). This request is $2.2 billion, or approximately 1%, higher than the corresponding appropriation for FY2016. In addition to the base budget request, the Administration requested $58.8 billion -- including $3.4 billion for the European Reassurance Initiative -- in discretionary funding for Overseas Contingency Operations (OCO). The total discretionary funding request of $609.9 billion, combined with $9.6 billion in mandatory spending, brought the Administration’s total FY2017 National Defense budget request to $619.5 billion. In shaping the FY2017 budget, DOD officials stated that they emphasized innovation and other ways to increase the combat effectiveness of U.S. forces while complying with the budget caps. The request aims to field a force that can deter the most technologically advanced potential adversaries using conventional weapons, without assuming that U.S. forces would match the size of enemy forces, by modernizing its equipment and changing its organization rather than by enlarging their numbers. This book provides an overview and analyses of the U.S. defense budget and OCO funding.