The design of RenderMan was driven by the requirements of rendering for the movies. The rendered images could have no digital artifacts and they had to be able to be composited seamlessly with live-action footage. This article recounts the development of RenderMan. It tells the story of the invention of the fundamental architecture and algorithms, the application of good engineering and design principles, RenderMan's use in feature films, the long-term influence of the RenderMan Shading Language on real-time graphics and high-performance computing, and, where the name came from.