Since 1982, Barry Posner and I have been working together to explore what leaders do to mobilize others and make them want to struggle for shared aspirations. Together, we have authored more than thirty publications, including books, workbooks, and assessment tools based on our research, including our best-selling book, "The Leadership Challenge." In 2008, we finished one of our most ambitious projects: analyzing 950,000 responses to our "Leadership Practices Inventory" (LPI) in eighty thousand personal assessments from leaders, and eight hundred and seventy thousand assessments from observers who know those leaders.

In recent days, I have stepped back to look at all this data from a distance and asked myself: If I were to make a list of the ten most important leadership lessons I have learned over all these years, what would those ten lessons be?

In the following lines, I present to you what I have come up with, and before continuing, it is worth reminding that we found much more than these ten lessons; this is not an exhaustive list, and you might find me changing it after a short period after further reflection on the subject.

1. Leadership is everyone’s business

2. Credibility is the foundation

3. Personal values drive commitment

4. Either lead by example or do not lead at all

5. Looking forward is an indispensable leadership pillar

6. It is not about the leader's vision alone

7. Challenges are the doors to achieving greatness

8. Leaders are team players

9. Leadership is a relationship

10. Caring is the heart of leadership

1. Leadership is Everyone’s Business All the time and wherever we look, we see leaders. They come from all types of organizations: public and private, governmental and non-governmental, high-tech and low-tech, large and small, in schools and professional services. We see among these leaders young and old, male and female, those who adhere to social ethics and those who deviate, and we see them in every ethnic group. They come from every profession and every field that can come to mind.

In other words, leadership is not a monopoly held by a handful of charismatic people who were naturally gifted with some kind of special power. Nor is leadership a matter of authority or influence gained by virtue of position and organizational environment. It is not a matter of your famous personality or your abundant wealth, nor your birth into a specific family, nor your holding of this high position at the top of a company, army, or ministry. And it is certainly not about being a hero.

Leadership is a set of skills and abilities that can be reached and taught to any human being who has the motivation and desire to learn them.

2. Credibility is the Foundation During those past twenty-six years, we have been asking people around the world this question: What do you require and value in a leader, that leader whose guidance you follow with conviction and willingness? (The key phrase in this question is “with conviction and willingness.”)

What we found from our research into the characteristics of a respected leader is that people demand, more than anything else, that the leader be credible. Simply, people need to believe in their leaders.

Because our research findings were widely noted and consistently highly rated, we have come to identify them as the: "First Law of Leadership." Credibility and trustworthiness are the "First Law of Leadership": If you don't believe in the messenger, you won't believe the message.

And what is trustworthiness behaviorally? How do you know it when you see it? When we asked these questions, the answers we received were essentially the same, regardless of the differences in expression. Credible leaders walk the talk; they practice what they demand of others, and they are consistent in their words and actions. They deliver what they promise. This led us to the "Second Law of Leadership": To be a credible leader, you must do what you say you will do.