Robert K. Greenleaf published two posthumous essay collections (available at Greenleaf.org). Today scores of colleges and universities include Servant Leadership in their curricula and hundreds of companies embrace Greenleaf's philosophy. As Greenleaf strived to serve through education, he became the leader of a movement. Bass, B. M., and Stogdill, R. M. (1990). "Bass & Stogdill's Handbook of Leadership: Theory, Research, and Managerial Applications" (3rd ed.). New York:Free Press. Frick, Don M. (2004)." Robert K. Greenleaf: A Life of Servant Leadership." San Francisco: Berrett-Koehler Publishers. Greenleaf, R.K. (2003). "The Servant-Leader Within: a Transformative Path" New York: Paulist Press. Greenleaf, R. K. (2002). "Servant Leadership:
James Greenleaf continued, however, to make the occasional visit to Allentown to see his wife. In the final few years of his life, his assistant was Bushrod Robinson—later a lieutenant in the Union Army, an important local businessman, and famous socialite in Washington. At the time he knew Greenleaf, Robinson was still in his early 20s. He described Greenleaf as tall, about , blond haired, clean shaven, courteous, and a great lover of children and books. (Greenleaf owned 2,612 books, which was an extremely large library for the day.) Around the first of September 1843, Greenleaf fell ill. His health did not