William Crowther is an American computer programmer, caver, and rock climber. He is the co-creator of Colossal Cave Adventure from 1975 onward, a seminal computer game that influenced the first decade of video game design and inspired the text adventure game genre.

Colossal Cave Adventure is a text-based adventure game, released in 1976 by developer Will Crowther for the PDP-10 mainframe computer. It was expanded upon in 1977 by Don Woods. In the game, the player explores a cave system rumored to be filled with treasure and gold. The game is composed of dozens of locations, and the player moves between these locations and interacts with objects in them by typing one- or two-word commands which are interpreted by the game's natural language input system. The program acts as a narrator, describing the player's location and the results of the player's attempted actions. It is the first well-known example of interactive fiction, as well as the first well-known adventure game, for which it was also the namesake.