In this chapter, the introduction to the book emphasizes why the U.N. Charter is the world’s most important secular document. The book aims to reintroduce the U.N. Charter to current generations of global citizens and to explain the U.N. Charter’s lasting significance in managing life on Planet Earth. The introduction examines the predecessor to the U.N. Charter, namely the Covenant of the League of Nations, before describing the historical meetings during World II leading to the drafting of the U.N. Charter, particularly at Dumbarton Oaks in Washington, D.C., in 1944 and in San Francisco, California, in 1945. The critical engagements of U.S. Presidents Franklin D. Roosevelt and Harry S. Truman, British Prime Minister Winston Churchill, and Soviet leader Joseph Stalin shaped the U.N. Charter’s content. Truman’s trilogy of addresses during those fateful days in 1945 illuminate what was at stake for the country and for the world. The various chapters of this book touch on interconnected issues addressed in other chapters, based on their shared focus on the U.N. Charter as a foundational document shaping global governance, human rights, and international law.