The U.S. Secret Service has two missions: criminal investigations and protection. Criminal investigation activities, which have expanded since its inception as a small anti-counterfeiting operation at the end of the Civil War, now encompass financial crimes, identity theft, counterfeiting, computer fraud, and computer-based attacks on the nation's financial, banking, and telecommunications infrastructure. Protection activities, which have expanded and evolved since the 1890s, include the safety and security of the President, Vice President, their families, and other identified individuals and locations. This book frames potential policy questions concerning the Service's mission and organisation through an examination of the U.S. Secret Service history and its statutory authorities, mission, and present activities within the Department of Homeland Security.