During the Revolutionary War he wrote 16 "Crisis" pamphlets, the first of which opened with the famous line "These are the times that try men’s souls." He also engaged in an important mission to raise funds in France for the destitute American army. In 1791, in response to Edmund Burke’s "Reflections on the Revolution in France", an attack on the French Revolution, Paine published his defense of the French Revolution: "Rights of Man" was a comprehensive defense of democracy that envisioned the modern welfare state. Paine’s next book, "Age of Reason" (1794), was an attack on organized religion from the deist point of view.

Paine failed far more often than he succeeded. Born in Norfolk, England, he had little education and failed at various occupations. He had two brief marriages. Somewhat ironically, one of his jobs while in England was to collect taxes from would-be smugglers. His life changed when he met Benjamin Franklin, who advised Paine to go to America and provided him with letters of introduction. At age 37 Paine arrived in America and very quickly began writing in defense of the American cause.

Despite his important role in the American Revolution, he remained a poor and controversial radical. He had even less luck in France, where he was imprisoned by the revolutionaries that he supported because he opposed the execution of the French King. He remained in France for eight years after being released from prison, and then returned to New York, where he lived in obscurity. He was not generally held in high regard at the time of his death; the most prominent obituary said "He lived long, did some good, and much harm." Only in the 20th century did Paine’s important contributions begin to be recognized.