Offering a unique resource for students, scholars, and citizens, this work fully explains all of the 21 enumerated powers of the U.S. Congress, from the "power of the purse" to the power to declare war. This work presents a comprehensive overview of the 21 congressional powers enumerated in the Constitution of the United States through essays that focus on each power. These informative essays introduce and explain each power individually, address its evolution from 1789 to the modern day and into the foreseeable future, and provide real-world examples of how each power has been applied through U.S. history. The comprehensive content enables an understanding of the mutually supporting interplay of all of the legislative powers in our government's system of checks and balances, and it allows readers to better appreciate how radical and daring the framers were at the Philadelphia convention in 1787. Readers will learn about Congressional powers that greatly impact modern citizens, many of which are frequently mentioned in news media due to policy struggles over budget, immigration, and national security; debates regarding the ideal size and role of government; and many others. The contributors also address questions regarding the responsibilities of the Congress, the ways in which Congress has met or failed to meet these responsibilities over the past two centuries, and what changes to congressional power may come in the future.