Once an Eagle is a 1968 war novel by American author Anton Myrer. A #1 New York Times Bestseller, Once an Eagle has been a favorite of American military men and women since its writing. The novel tells the story of Sam Damon, career Army officer, from his initial enlistment to his rise to general officer rank. Myrer wrote his novel to warn against ambition without principle and the military-industrial complex. Sam Damon and Courtney Massengale are the vehicles for this warning. Damon is an honorable soldier who rises in rank by success in field command. He is a soldier of character with his men's welfare in mind. Massengale has no honor and rises in rank through staff positions by cunning and political connections. He is driven by lust for power and cares nothing for the welfare of soldiers. A television mini-series based on the book was aired on NBC in 1976, with actor Sam Elliott portraying Sam Damon. The book appears on the Commandant's required reading list for all First Lieutenants in the United States Marine Corps, and frequently serves as a text for cadets in leadership classes at West Point.