Harry Hart "Pat" Frank (May 5, 1907 – October 12, 1964) was an American newspaperman, writer, and government consultant. Perhaps the “first of the post-Hiroshima doomsday authors,” his best known work is his post-apocalyptic novel Alas, Babylon (1959), which depicted the outbreak of a nuclear war and the struggles of its survivors in a small, central Florida town.

"Pat Frank" was the lifelong nickname adopted by the American writer, newspaperman, and government consultant, who was born Harry Hart Frank. He is remembered today almost exclusively for his post-apocalyptic novel Alas, Babylon. Before the publication of his first novel Mr. Adam, which launched his second career as a novelist and independent writer, Frank spent many years as a journalist and information handler for several newspapers, agencies, and government bureaus. His fiction and nonfiction books, stories, and articles made good use of his years of experience observing government and military bureaucracy and its malfunctions, and the threat of nuclear proliferation and annihilation. After the success of Alas, Babylon, Frank concentrated on his writing.