The best way to study leadership is to study leaders. How they exercised influence in their contexts provides examples of how we can do so in ours. For this reason, it is paramount for leaders to be well-versed in biography and history, the knowledge of people and their times.Doris Kearns Goodwin’s Leadership in Turbulent Times provides case studies of the leadership of four U.S. presidents at critical junctures in their administrations:• Abraham Lincoln exemplifies transformational leadership as he expanded the North’s war aims from union to emancipation through the issuance of the Emancipation Proclamation.• Theodore Roosevelt provides a model of crisis management by how he brought labor and management to the table during the Great Coal Strike of 1902.• Exuding optimism and executing a plan to respond to the Great Depression in his first 100 days, Franklin Delano Roosevelt offers a master class in turnaround leadership.• And Lyndon Johnson demonstrates visionary leadership by using all the forces at his disposal — including persuasion and hardball politics — to pass the Civil Rights Act (1964) and Voting Rights Act (1965), fundamentally altering the legal terms under which whites and blacks related to one another.Goodwin presents these case studies in Part III of her book, “The Leader and the Times: How They Led.” Of each president’s White House years, she writes: “There, at their formidable best, when guided by a sense of moral purpose, they were able to channel their ambitions and summon their talents to enlarge the opportunities and lives of others.”But those ambitions and talents didn’t emerge de novo or ex nihilo. The four presidents were influenced by circumstances just as much as they in turn influenced them. Part I, “Ambition and the Recognition of Leadership,” narrates the burgeoning sense of possibility each president experienced in his 20s especially, along with the recognition by their peers that they were destined for greater things. Part II, “Adversity and Growth,” shows how each one faced a test or series of tests that forced them to ask deeper questions of their life’s meaning — questions that, once answered, steeled their commitment to lead. Finally, an Epilogue examines how each man reflected on his enduring reputation, a fame that would last beyond both his administration and his death. How would they be remembered by posterity?As with Goodwin’s previous works on these four presidents, Leadership in Turbulent Times is a gripping read, combining biographical detail and historical context. It is the addition of shrewd insights about leadership throughout the book that marks a departure from her earlier biographies. Those insights are well-grounded and explicit.One of the great dangers of drawing lessons from biography or history is that such lessons smooth over differences, whether among the subjects of biographical inquiry, or between their times and our own. Doris Kearns Goodwin is well aware of this danger and largely avoids it. The leadership principles she draws organically arise from the events she narrates. Here’s how she explains the matter in the book’s Foreword:"These four extended examples show how their leadership fit the historical moment as a key fits a lock. No key is exactly the same; each has a different line of ridges and notches along its blade. While there is neither a master key to leadership nor a common lock of historical circumstance, we can detect a certain family resemblance of leadership traits as we trace the alignment of leadership capacity within its historical context."That “family resemblance of leadership traits,” the book’s explicit lesson, is what leaders will most appreciate about Leadership in Turbulent Times. Its implicit lesson is that leaders must know themselves and their own times if they want to change them. Leadership never occurs in a vacuum where principles can be applied automatically. Rather, it requires wisdom. Like the biblical men of Issachar, leaders understand the times and know just what to do (1 Chronicles 12:32).