Summary: GAO discussed the Department of Defense's (DOD) dependence on foreign sources for critical components of its weapons systems. GAO noted that: (1) DOD had limited information and lacked a reliable information system on foreign sources and dependencies, and did not know the overall extent of its foreign sourcing and dependency; (2) DOD had no criteria for determining appropriate levels of foreign dependency tolerance for various items or for determining actions it should take to reduce the associated risks of such dependency; (3) potential disadvantages to foreign dependency included the generally greater unreliability of foreign than domestic sources, lack of access to advanced technology, and reduced domestic production capabilities; (4) DOD did little to reduce its long-standing foreign dependency regarding two items; and (5) DOD efforts to improve its information on the U.S. defense industrial base and revise acquisition directives and procedures to include early consideration of foreign sourcing issues have been slow and have significant limitations.