Maxwell is a name for leadership (not just coffee).
In Developing the Leader Within You, John Maxwell outlines several areas to grow as a leader. These include:
Defining leadership by Influence
Priorities are the key to leadership
Integrity is the most important ingredient
The ultimate test of a leader is creating positive change
And many other topics.
Maxwell's books read very quickly and easily. You'll find a number of anecdotes and quotes from a wide variety of leaders in all fields.
Bottom line - if you want to be a leader, you need to have a positive influence over people. That is how it works. Without people, you're just a guy taking a walk. (as they say)