I recently finished reading "Leaders At All Levels" by Ram Charan and would recommend it as part of your professional leadership library. Ram Charan is a world-renowned advisor to business leaders and corporate boards as well as best selling author or co-author of 14 books. He zeroes in on different ways to ensure organizations have the quality and quantity of leaders in their ranks to ensure continuity of leadership.
I especially found his views on how to spot and develop leaders within the organization to be insightful. In one section in particular, he states, "The military is another source of leadership talent. Its leadership training is second to none." As I reflected on why I integrate military leadership lessons into my leadership practice, it occurred to me it wasn't that I was just learning how to lead, but rather I was learning to lead extremely well under adverse circumstances that makes a difference.