Works of American science-fiction writer Robert Anson Heinlein include Stranger in a Strange Land (1961) and The Moon Is a Harsh Mistress (1966). People often call this novelist "the dean of science fiction writers", one of the most popular, influential, and controversial authors of "hard science fiction." He set a high standard for science and engineering plausibility and helped to raise the standards of literary quality of the genre. He was the first science-fiction writer to break into mainstream, general magazines such as The Saturday Evening Post, in the late 1940s. He was also among the first authors of bestselling, novel-length science fiction in the modern, mass-market era. Also wrote under Pen names: Anson McDonald, Lyle Monroe, Caleb Saunders, John Riverside and Simon York.