By Chad Brooks

Throughout history, much has been written about what it means to be a leader. Ancient Chinese military general and "Art of War" author Sun Tzu described a leader as one who "cultivates the moral law, and strictly adheres to proper methods and discipline." Nineteenth-century historian Thomas Carlyle believed leaders were born and not made, while English philosopher Herbert Spencer argued that leaders were the result of the society in which they lived.

The decades that followed brought countless studies and research reports that detailed a wide variety of leadership skills, styles and characteristics, with researchers identifying distinct leader "types." Some authors even devoted their work to all the personal factors that influence an individual's approach to management.

With all of these differing schools of thought, it's clear that there's no single definition of leadership. What works for one leader may not necessarily work for another, depending on the circumstances and personality type. But there's one thing that nearly every academic, historian and even leaders themselves agree upon: A true leader must be able to inspire his or her team.

Leaders can get the best out of people. "Today's top leaders are consistent with their approach, get their hands dirty and create a company culture that will last long after he or she . 'Comfort zones' are almost nonexistent under strong leadership, because each team member is pushed to their full potential. Great leaders also hire and inspire other great leaders, whom they trust to carry out the company mission and instill a sense of purpose that touches each and every staff member." — Tom Villante, co-founder, chairman and CEO of payment processing company YapStone.

Leadership is all about giving and serving. "It is lonely at the top, but that's no excuse for not giving generously of your time, your experience and your encouragement to your team — and never expecting any of that in return. You are the person in the unique position of finding or uncovering strengths in people, leveraging them and celebrating them. If you're going to lead, and lead well, you have to put it all out there every day, regardless of the outcome. Leaders who hold back will eventually hold their teams back." — Tricia Sciortino, president of eaHELP, a provider of virtual assistant services.

Leadership requires ambition. "Leaders are described with a mouthful of adjectives, such as passionate, visionary, charismatic, motivational and encouraging. However, I propose leadership is something simpler. It is ambition. Ambition creates hard work, determination and an unconditional desire to achieve. It generates an absolutely contagious energy that people follow and join naturally. If you are a leader in your organization, there is only one thing you need to understand about your role: never let your ambition fade." — Corey Baggett, co-founder of ad technology firm AdBoom Group.

Good leaders have a good attitude. "A good leader can hold his or her emotions in check, especially in tough situations. For example, maybe you lost your best client, or a deal you've been working on falls through. Regardless, it's important for leaders to guide a team through challenging times, encouraging them and remaining positive along the way. Team morale is heavily contingent upon a leader's attitude." — David Moore, founding partner and regional vice president of Addison Group staffing firm.

Leadership means being in touch with your people. "A leader places the people around him or her in a position that sets them up for success. This is a difficult task, because a leader must have an in-depth understanding of each individual, such as understanding their career goals and knowing what motivates them. By being committed to helping each person achieve their own personal goals, the leader sets the organization up for greatness. Leaders are good listeners. They listen to verbal and nonverbal cues to understand occurring in the organization. This allows you to address problems before they become big issues." — Andor Kovacs, CEO and founder of property restoration brand Restoration 1.

Leaders set the right example. "Leadership is setting an example in the way you act each day, while focusing on the bigger picture. It's about setting the tone for your team and organization in the way you interact with your own staff, your business partners and your customers. As a leader, it is your responsibility to establish goals, innovate, motivate and trust. A passionate and compassionate leader can energize a company. Set an example of cooperation, trust and openness. Focus on solutions and positivity instead of finding faults and blame for actions." — Richard Kissane, president and CEO of Premium Franchise Brands, parent company of JAN-PRO and Maid Right Franchising.

Leaders can't stand alone. "The out-and-out leader in today's volatile and uncertain business environment had better not distance him or herself from the heat of the action. Demonstrating the competence to assess, decide and execute in a growing business drives confidence in the leader. Similarly, a great leader of an enterprise stands on the shoulders not of 'managerial Muppets' who obediently do as they are directed, but of other leadership giants who have different and complementary leadership skills. A business with only one leader will remain forever a small business." — Richard Hytner, deputy chairman of Saatchi & Saatchi Worldwide and author of "Consiglieri: Leading from the Shadows".