Computational notebooks were introduced by Mathematica in 1988; the Jupyter Notebook is our concrete realization of the computational narrative, with a web-based architecture designed for extensibility, programming language independence, and an open document format. The raw events of this narrative are the input (code) and output of the iterations of the REPL/WETL of the underlying interactive computation. Around that, the user can add narrative text including equations, multi-media content, and more.