The Department of Defense (DOD) supply chain is vulnerable to the risk of counterfeit parts, which have the potential to delay missions and ultimately endanger service members. To effectively identify and mitigate this risk, DOD began requiring its agencies in 2013 and its contractors in 2014, to report data on suspect counterfeit parts. This book examines, among other things, the use of the Government-Industry Data Exchange Program (GIDEP) to report counterfeits; GIDEP’s effectiveness as an early warning system; and DOD’s assessment of defense contractors’ systems for detecting and avoiding counterfeits.