"Myst is a franchise centered on a series of adventure video games. The first game in the series, Myst, was released in 1993 by brothers Rand and Robyn Miller and their video game company Cyan, Inc. Riven, the sequel to Myst, was released in 1997, and was followed by three more direct sequels: Myst III: Exile in 2001, Myst IV: Revelation in 2004, and Myst V: End of Ages in 2005. A spinoff featuring a multiplayer component, Uru: Ages Beyond Myst, was released in 2003 and followed by two expansion packs.
Myst's story concerns an explorer named Atrus who has the ability to write books which serve as links to other worlds, known as Ages. This practice of creating linking books was practiced by an ancient civilization known as the D'ni, whose society crumbled after being ravaged by disease. The player takes the role of an unnamed person referred to as the Stranger and assists Atrus by traveling to other Ages and solving puzzles. Over the course of the series Atrus writes a new Age for the D'ni survivors to live on, and players of the games set the course the civilization will follow."
Source: Wikipedia, "Myst_(series)", available under the CC-BY-SA License.