Leadership at its core is about harnessing others' efforts to achieve something no one can achieve alone. It's about helping people go as far as they can with the talents and skills they have.

That definition is simply this: Leadership is the art of getting people to want to do what must be done.

Notice three things about this definition. First, as a leader, it’s your responsibility to figure out what must be done. You might do this by your own insight and instinct or, more likely, via dialogue and debate with the right people; but however you do it, you need to get clear. Second, it’s not about getting people to do what must be done but about getting them to want to do it. Third, it’s not a science; it’s an art.

But the evidence-based view of a leader is that of someone able to align a group in the pursuit of a common goal. Accordingly, some people may not be in a position of authority but may act as leaders by encouraging people to work together as a coordinated unit. Likewise, some individuals formally in charge may not be operating as leaders or may have little talent for shaping a winning team. This conflict between true ability and a leadership assignment often arises when employees are rewarded with a leadership role because of their past performance as individual contributors. Under these circumstances, leadership is more of a symbolic title or recognition for past efforts, rather than an actual resource for the team or organization.

Leadership is a quality rather than a job. We are all leaders and followers at different points in our lives. Many aspects of this book should be useful to those looking to grow as leaders as well as managers, and great managers should cultivate leadership not just in themselves but also within their teams.

This is an important distinction because while the role of a manager can be given to someone (or taken away), leadership is not something that can be bestowed. It must be earned. People must want to follow you.

A classic definition of leadership is inspiring others to perform and achieve a shared vision. This is true, but I would rephrase this definition of leadership as the art of building trust and meaningful connections in an environment where results matter. The leader is in charge of supporting the team, and this requires interdependence: being in relationship with others who depend on you just as you depend on them.