The successor states of the former Soviet Union have enormous stocks of weapons-usable nuclear material and other militarily significant commodities and technologies. Preventing the flow of such items to countries of proliferation concern and to terrorist groups is a major objective of U.S. national security policy. This book reviews the effectiveness of two U.S. programs directed to this objective. These programs have supported the efforts of Russia, Ukraine, Belarus, and Kazakstan in upgrading the physical protection, control, and accountability of highly enriched uranium and plutonium and strengthening systems to control the export of many types of militarily sensitive items.