When it comes to the Founding Fathers, Thomas Jefferson, Benjamin Franklin, and Alexander Hamilton are generally considered the great minds of early America. George Washington, instead, is toasted with accolades regarding his solid common sense and strength in battle. Indeed, John Adams once snobbishly dismissed him as "too illiterate, unlearned, unread for his station and reputation." Yet Adams, as well as the majority of the men who knew Washington in his life, were unaware of his singular devotion to self-improvement. Based on a comprehensive amount of research at the Library of...