In her new book, Harvard historian Nancy Koehn makes the case that leaders aren’t born — they’re made.

Koehn draws leadership lessons from profiles of explorer Ernest Shackleton, President Abraham Lincoln, abolitionist Frederick Douglass, clergyman and anti-Nazi dissident Dietrich Bonhoeffer, and environmentalist Rachel Carson. The resulting book, "Forged In Crisis: The Power of Courageous Leadership in Turbulent Times," is both an engaging history and a guidebook of sorts for leaders facing difficult situations of their own.

"In huge change, in turbulence, leaders not only have to make the kinds of decisions about military command or politics or thinking about the people around them. They also have to communicate and frame the turbulence to all the people around them," Koehn explained.

"I make the argument that crisis leadership is actually about that kind of communication and framing as much as about the specific actions," she said.

Click the audio player above to hear more from Nancy Koehn.