Nat Schachner

Best known for his biographies of American historical figures such as Thomas Jefferson and Alexander Hamilton, and as the creator of the Grandfather paradox, Schachner began his writing career contributing short stories to leading "pulp magazines" that specialized in science fiction, horror, mystery, and adventure genres. During the heart of the Great Depression, he contributed more than fifty stories to magazines such as ''Astounding Stories'', ''Terror Tales'', ''Horror Stories'', ''Dime Mystery Magazine'', and ''Fantastic Adventures''. He then turned to writing historical non-fiction and fiction, gaining recognition for his prodigious research.
Schachner, a practicing attorney, was a founder and officer of the American Interplanetary Society, which pioneered liquid fuel rocketry in the United States in the early 1930s. Later known as the American Rocket Society, the organization eventually became part of the American Institute of Aeronautics and Astronautics, a professional society in the field of aerospace engineering that today has nearly 30,000 members world-wide. Provided by Wikipedia