From the introduction:
Story Engine was born in 1996 as the rules system for Maelstrom Storytelling. It was subsequently redesigned as a universal rules system in 1999. One of the initial games to truly handle roleplaying as a storygame, Story Engine was the first to focus on scenes rather than turns-- an idea that has become more and more popular over the years. Story Engine also further evolved the mechanics of adjective-based characters, an idea that had appeared in earlier games, as well as various diceless mechanics.
Story Bones is the introductory version of Story Engine, stripped to its most fundamental parts. The system is fully-functional and ready to run, but like any lite version of a game, the mechanics have been distilled to their most-basic components for simpler and faster play.