Modest Stein (1871–1958), born Modest Aronstam, was a Lithuanian Jewish and American illustrator and close associate of the anarchists Alexander Berkman and Emma Goldman. He was Berkman's cousin and intended replacement in the attempted assassination of Henry Clay Frick, an industrialist and union buster, in 1892. Later Stein abandoned active anarchism and became a successful newspaper, pulp magazine, and book illustrator, while continuing to support Berkman and Goldman financially.

Alexander Berkman was a Russian-American anarchist and author. He was a leading member of the anarchist movement in the early 20th century, famous for both his political activism and his writing.