Forbes was the author of six historical novels and four books of nonfiction for adults, as well as the recipient of the Pulitzer Prize in history in 1942 for her adult biography, Paul Revere and the World He Lived In Paul Revere and the World He Lived In (1942). Yet Forbes's reputation is primarily as a children's writer, resting particularly on Johnny Tremain (1942), an offshoot of her research for the adult Paul Revere biography and considered by many the best example of historical fiction ever written for children. Johnny Tremain follows the story of a silversmith's apprentice as he stumbles into the American Revolution and gains insight into his own character. In writing about the life of an ordinary citizen of Boston at that time, Forbes wanted to show, in her words, "not merely what was done but why and how people felt." Originally intending to keep Johnny neutral during the Revolution, she changed her mind as a result of the advent of World War II, because she saw parallels between the two wars and wanted to show young readers those parallels. Although this may have resulted in some pushing of contemporary ideology onto a historical setting, most critics have praised the story's accuracy. It was and remains an important book for promoting the idea that young readers can grasp mature writing. Forbes's only other book for children, America's Paul Revere, summarizes that man's life.