During the 1940s, Rand became politically active. She and her husband worked as full-time volunteers for the 1940 presidential campaign of Republican Wendell Willkie. This work led to Rand's first public speaking experiences; she enjoyed fielding sometimes hostile questions from New York City audiences who had viewed pro-Willkie newsreels. This activity brought her into contact with other intellectuals sympathetic to free-market capitalism. She became friends with journalist Henry Hazlitt and his wife, and Hazlitt introduced her to the Austrian School economist Ludwig von Mises. Despite her philosophical differences with them, Rand strongly endorsed the writings of both men throughout her career, and both of them expressed admiration for her. Mises once referred to Rand as "the most courageous man in America", a compliment that particularly pleased her because he said "man" instead of "woman". Rand also became friends with libertarian writer Isabel Paterson. Rand questioned Paterson about American history and politics long into the night during their many meetings and gave Paterson ideas for her only non-fiction book, "The God of the Machine".