Immanuel Velikovsky was a Russian-American psychoanalyst, writer, and catastrophist. He is the author of several books offering pseudohistorical interpretations of ancient history, including the U.S. bestseller Worlds in Collision published in 1950. Velikovsky's work is frequently cited as a canonical example of pseudoscience and has been used as an example of the demarcation problem.

Harlow Shapley was an American scientist, head of the Harvard College Observatory (1921–1952), and political activist during the latter New Deal and Fair Deal.