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:
Follett's Modern American Usage place on the shelf beside Fowler." Poet and critic Mark Van Doren wrote "This is a book that any conscientious writer will continue to consult as long as he lives." Clifton Fadiman wrote: "A work comparable to Fowler's classic "Modern English Usage". Eliot Fremont-Smith wrote in "The New York Times": "Few have been more outspoken [in their attack on the permissive view] than the late Wilson Follett; and his "Modern American Usage" ... may be taken as the most detailed and sustained attack so far on the notion that anything goes – or should go." The critic and author Louis