How did Kissinger prepare for his first major job in the U.S. government as national security advisor to President Richard Nixon? In his words, “When I entered office, I brought with me a philosophy formed by two decades of the study of history.” Ferguson uncovered a fascinating fragment from one of Kissinger’s contemporaries when they were both first-year graduate students at Harvard. John Stoessinger recalled Kissinger arguing “forcefully for the abiding importance of history.” In these conversations, Stoessinger said, Kissinger would cite the assertion by the ancient Greek historian Thucydides that “The present, while never repeating the past exactly, must inevitably resemble it. Hence, so must the future.”

“More than ever,” Kissinger urged, “one should study history in order to see why nations and men succeeded and why they failed.”

Ferguson has crafted his biography of Kissinger not only as the definitive account of an incredible personal and intellectual odyssey, but also as an opportunity to initiate a debate about the importance of history in statecraft. The book plants a flag for a project in “Applied History,” which he and I have been gestating at Harvard for several years. By Applied History we mean the explicit attempt to illuminate current policy challenges by analyzing historical precedents and analogues. Following in the footsteps of the 1986 classic Thinking in Time by Ernest May and Richard Neustadt, our goal is to revitalize Applied History both as a discipline in the university and as an art in the practice of statecraft.

How does Kissinger apply history? Subtly and cautiously, recognizing that its proper application requires both imagination and judgment. As Kissinger put it, “History is not … a cookbook offering pretested recipes. It teaches by analogy, not by maxims.” History “can illuminate the consequences of actions in comparable situations.” But—and here is the key—for it to do so, “each generation must discover for itself what situations are in fact comparable.”

Ferguson’s biography offers an array of examples of when Kissinger drew comparable analogues from history to illuminate contemporary issues and choices. For clues in coping with the frequently frustrating behavior of French President Charles de Gaulle in the 1960s, Kissinger suggested thinking about German leader Otto von Bismarck. For instance, responding to de Gaulle’s moves toward European confederation and away from American influence, Kissinger noted that the French president’s “diplomacy is in the style of Bismarck, who strove ruthlessly to achieve what he considered Prussia’s rightful place, but who then tried to preserve the new equilibrium through prudence, restraint, and moderation.” This insight led Kissinger to conclude that de Gaulle was a self-interested but reasonable leader whom the United States could deal with, at a time when many were ready to write de Gaulle off as a communist sympathizer for being the first Western leader to recognize Maoist China in 1964.