What is the theme in Washington, the Indispensable Man by James Thomas Flexner?

Duty is the main theme of this book. From a young age, Washington feels a sense of duty to his home and family, especially to his mother who comes to rely heavily on Washington after her husband's death. Caring for the family's land and heritage is paramount to the young man, who soon learns that this will be the driving force of his life: taking care of a country and the people who inhabit it. As a fledgling soldier, Washington is loyal to his mission and to the people who serve with him, staying the course when other young men may have run when faced with the horrors of primitive warfare.