President Franklin D. Roosevelt signed the Atlantic Charter in 1941 promoting the world's decolonization. US granted independence to the Philippines and created the perception of decolonizing Puerto Rico with the establishment of the Commonwealth. This is the story of President Harry S. Truman and his principal advisor, Fleet Admiral William D Leahy (former Governor of Puerto Rico) role in creating the perception of Puerto Rico's decolonization. Truman appointed the first Puerto Rican governor; approved the law for Puerto Ricans to elect their governor and the Commonwealth of Puerto Rico new Constitution. The book covers the controlling role of the US Navy over Puerto Rico and the island's protagonism during World War II and the Cold War.