It’s all based on a book by French author Pierre Boulle. In said novel, an interplanetary expedition comes across a planet where apes rule and humans are used for slave labor and experiments. Famed writer Rod Serling took the first crack at the screenplay, though his ideas were deemed too expensive and incendiary to film. Blacklisted scribe Michael Wilson was then brought in to bring the concepts down to budgetary (and moviegoer) limits, and soon a sci-fi classic was born.
Audiences were not prepared for Planet of the Apes when it first came out in theaters. The Civil Rights Movement was reeling from advances and assassinations and Serling’s subtext made the roots of said racism all too real. While further script doctoring decreased some of the more provocative material, the notion of Apes as an allegory for its time remained. It was a box office smash, jumpstarting a franchise which saw four initial sequels, two reboots, one follow-up to same, and even a TV series.