The life of Franklin Roosevelt's most trusted and powerful advisor, Admiral William D. Leahy, Chief of Staff to the Commander-in-Chief

“Fascinating… greatly enriches our understanding of Washington wartime power.”—Madeleine Albright

Aside from FDR, no American did more to shape World War II than Admiral William D. Leahy--not Douglas MacArthur, not Dwight Eisenhower, and not even the legendary George Marshall. No man, including Harry Hopkins, was closer to Roosevelt, nor had earned his blind faith, like Leahy. Through the course of the war, constantly at the president's side and advising him on daily decisions, Leahy became the second most powerful man in the world.

In a time of titanic personalities, Leahy regularly downplayed his influence, preferring the substance of power to the style. A stern-faced, salty sailor, his U.S. Navy career had begun as a cadet aboard a sailing ship. Four decades later, Admiral Leahy was a trusted friend and advisor to the president and his ambassador to Vichy France until the attack on Pearl Harbor. Needing one person who could help him grapple with the enormous strategic consequences of the war both at home and abroad, Roosevelt made Leahy the first presidential chief of staff--though Leahy's role embodied far more power than the position of today.

Leahy's profound power was recognized by figures like Stalin and Churchill, yet historians have largely overlooked his role. In this important biography, historian Phillips Payson O'Brien illuminates the admiral's influence on the most crucial and transformative decisions of WWII and the early Cold War. From the invasions of North Africa, Sicily, and France, to the allocation of resources to fight Japan, O'Brien contends that America's war largely unfolded according to Leahy's vision. Among the author's surprising revelations is that while FDR's health failed, Leahy became almost a de facto president, making decisions while FDR was too ill to work, and that much of his influence carried over to Truman's White House.
“Compelling.”—Foreign Affairs

“[A] first-rate biography…O’Brien recounts [Leahy’s] astounding career in fascinating detail.”—The Christian Science Monitor

“Whether it's the conferences at Tehran, Yalta, or Potsdam, Admiral Leahy stands out in the iconic photographs, in full uniform, just behind the Big Three. Why, though, was he there, and in so many other places that shaped the conduct of World War II and the early Cold War? As if more impressed by the uniform than by the man, historians until now have struggled to say. Phillips Payson O'Brien's biography at last gives Leahy his due, and in doing so shifts our understanding of the other great figures of that era. We're all going to have some serious rethinking to do.”—John Lewis Gaddis, Professor of Military and Naval History at Yale University and Pulitzer Prize-winning author of George F. Kennan: An American Life
“With his fascinating new biography of Admiral William D. Leahy, Phillips Payson O’Brien takes readers behind the closed doors of Franklin Roosevelt’s White House to reveal how the biggest strategic decisions of World War II were actually made. The Second Most Powerful Man in the World greatly enriches our understanding of Washington wartime power.”—Former Secretary of State Madeleine K. Albright
“Phillips Payson O’Brien’s The Second Most Powerful Man in the World is a beautifully written and thoroughly researched biography of Admiral William D. Leahy. In so many ways, Leahy was FDR’s indispensable strategist. In these pages are magnificent stories about Pearl Harbor, Vichy France, and Winston Churchill. Highly recommended!”—Douglas Brinkley, Professor of History at Rice University and New York Times bestselling author of Rightful Heritage: Franklin D. Roosevelt and the Land of America
“In the story of how allied strategy was determined in World War II, there has long been a major gap. What made the relationship between Roosevelt and his Joint Chiefs actually tick? In this readable and revisionist biography of William D. Leahy, Phillips Payson O'Brien provides an answer that transforms our understanding of America's wartime decision-making. Leahy has been hiding in plain sight. Now that he has found his spotlight, we shall need to rethink some of our most cherished assumptions.”—Hew Strachan, Emeritus Fellow of All Souls College, Oxford and author of The Direction of War

“A welcome biography of Franklin Roosevelt's closest adviser... A lucid, opinionated life of a man who exerted far greater influence than historians give him credit for—and a book sure to invite spirited argument from historians who disagree.”Kirkus (starred review)

“Engaging… Excels at relating the political maneuvering that allowed [Leahy] to repeatedly upstage better-known historical figures including George Marshall and Douglas MacArthur… This is a solid and informative account of a relatively underdiscussed influence on Cold War policies, worldviews, and relationships that still matter today.”—Publishers Weekly

“An excellent biography of perhaps the most notable navy officer in American history, and one of the most important, if neglected, figures in World War II history.”Library Journal