Robert Anson Heinlein was an American science fiction writer, often referred to as "the dean of science fiction writers." He was one of the most popular, influential, and controversial authors in the genre. Heinlein set a high standard for scientific and engineering plausibility, elevating the literary quality of science fiction.

He was among the first writers to successfully publish in mainstream magazines, such as The Saturday Evening Post, in the late 1940s with what was then unvarnished science fiction. As one of the first bestselling novel-length science fiction authors in the modern, mass-market era, Heinlein, along with Isaac Asimov and Arthur C. Clarke, was considered one of the "Big Three" of science fiction.

Heinlein's work often included admiration for competence and critical thinking, while his plots frequently challenged conventional social norms. His influence extends beyond the science fiction genre to modern culture.

He explored provocative social and political ideas through his writing, speculating on how scientific and technological advances might shape the future of politics, race, religion, and sex. His stories often addressed social themes such as individual liberty, the nature of sexual relationships, societal obligations, the influence of religion on culture and government, and the repression of nonconformist thought.

Heinlein was a progressive liberal early in life but started adopting conservative viewpoints later, advocating for strong world government as a means to prevent nuclear annihilation. Named the first Science Fiction Writers Grand Master in 1974, Heinlein won four Hugo Awards, and several of his novels were awarded "Retro Hugos."

Notable works include Stranger in a Strange Land, Starship Troopers, and The Moon Is a Harsh Mistress. His fiction introduced terms such as "grok," "waldo," and "speculative fiction" to the English language.