Nelson Aldrich Rockefeller was born in Bar Harbor, Maine, on July 8, 1908, the third of six children of John B. Rockefeller Jr., and Abby Greene Aldrich. His grandfathers were John D. Rockefeller Sr. (1839-1937), founder of the Standard Oil Company, and U.S. senator Nelson Aldrich (1841-1915) of Rhode Island. Rockefeller attended Dartmouth University, where he majored in economics, taught a Sunday school class, and occasionally worked in the school cafeteria to earn spending money. In 1930, he married Mary Todhunter Clark, a Philadelphia socialite. They had five children.

At age thirty, he was president of the New York Rockefeller Center, a famous grouping of office buildings in central Manhattan. Several trips to Latin America in the late 1930s convinced him of the region's importance to national security. In 1940, Rockefeller accepted his first major governmental position as the head of the Office of Inter-American Affairs. For his effectiveness...