Imagine you're sitting in a meeting with your colleagues at work, and in walks someone you've never met before. This person says, "Hi, I'm your new leader." What questions immediately come to mind that you would want to ask this person?

As it turns out, best-selling authors and prolific leadership educators, Barry Posner and James Kouzes, spent 30 years pouring over their research data from over a million respondents to discover what has been consistently true about leadership over the years.

In The Truth About Leadership, the formula for exceptional leadership -- across generational lines (these time-tested truths are effective on Millennials, Gen Xers nad Boomers alike) -- is finally revealed for us all.

The 10 Truths About Great Leadership

1.  You believe in yourself. It all starts with the fundamental belief that you can make a difference and you will have a positive impact on others.

2. You have credibility. Your people have to believe in you, too. If people don't believe in you, they won't willingly follow you.

3. Your values drive commitment. Your people want to know what you stand for and believe in, and that your values align with theirs.

4. You have vision. Focusing on the future and having a long-term perspective sets leaders apart. You imagine and articulate exciting possibilities for your followers.

5. You know you can't do it alone. Being surrounded with support and talent, and engaging the team in pursuing the cause sets you apart. While that sounds obvious enough, the difference in the research is that great leaders are obsessed with what is best for others, not what is best for themselves.

6. You give trust before you get trust. If you have to rely on a team, trust is the social glue that holds the team together. And the level of trust your people have in you will determine the amount of influence you have. The key? Earn their trust before they'll be willing to trust you.

7. You welcome challenges. Great accomplishments don't happen when you keep things the same. Change involves challenge, and challenge tests you. Great leaders step up to the challenge, and come face-to-face with their level of commitment. A great challenge will reveal your grittiness and mindset about change.

8. You either lead by example or you don't lead at all. Leaders have to keep their promises and become role models for the values and actions they espouse. You can't ask others to do something you aren't willing to do yourself. And, you admit mistakes and learn from them.

9. You are a great learner. You have to believe that you can become a better leader tomorrow than you are today. This takes constant improvement, practice, feedback, good coaching, and a willingness on your part to ask for support.

10. You are motivated by love. You love your employees, customers, and the mission you are serving. Since leadership is an affair of the heart, the best leaders have been shown to be motivated by the love that energizes them to give much to others. You just won't work hard enough to become great if you aren't doing what you love.

Final Thoughts

So there you have it--what Posner and Kouzes say are the fundamental, enduring truths of leadership that hold constant regardless of context, circumstance, age, or industry.

Use these to do the real work of bringing about change in your organization, and building up new leadership talent in your pipeline.