The 21 Irrefutable Law of Leadership - For starter, Maxwell has earned high praise and respect across a diverse global audience. He attracts requests for speaking engagements and leadership consulting across a wide range of organization from Fortune 500 companies, international governments, the United States Military, to the National Football league. John Maxwell's The 21 Irrefutable Law of Leadership is a book that i have found quite helpful in measuring my own personal growth in leadership abilities, as well as in finding the areas where I struggle or need to grow.