Robert A. Heinlein (1907–1988) was one of the most influential science fiction writers of the 20th century and is often considered one of the “Big Three” of classic science fiction alongside Isaac Asimov and Arthur C. Clarke. His work helped shape modern science fiction by introducing more realistic science, complex social ideas, and adult themes into the genre.

Heinlein had a profound impact on both science fiction and broader culture. He helped move science fiction from pulp adventure stories into more serious literature that explored politics, philosophy, and social change. His works influenced scientists, engineers, and space enthusiasts during the early space age, and he is often credited with inspiring interest in space exploration.

His novel Stranger in a Strange Land became especially influential during the 1960s counterculture movement, while Starship Troopers helped define the military science fiction subgenre.