Too Long; Didn't Read
“Notebooks” are web applications that run on the browser that give you, the user, an interface to a virtual machine that runs an out-of-the-box environment. They are based on the Jupyter Notebook project — an open-source project that brings machine learning development to your browser. Notebooks reduce the time that a developer takes to set up his/her environment: install packages, update them to the required versions, and any other network or file-structure configurations that take time to set-up. And all that needs to be done BEFORE jumping into developing the apps themselves.