This report is a comprehensive overview of oversight conducted over the past decade to measure how well DHS is achieving its mission, operating its programs, spending taxpayer funds, complying with the law, and respecting the boundaries established to limit the federal government and protect the rights of law abiding U.S. citizens. Created after the September 11, 2001 terrorist attacks, DHS is the result of the largest reorganization of government in more than a half century. Today, the Department's spends approximately $61 billion annually and employs more than 240,000 people. It includes many different components, directorates, offices, and programs with a broad range of missions. This report reviews each of DHS's five main missions, where it is falling short with each, and provides recommendations to make the Department more efficient and effective. The analysis is based upon independent information and evidence as well as oversight conducted by my office and other watchdogs. Where necessary, this report notes where additional oversight is needed to improve transparency and understanding of DHS's programs and performance.