Babel is Org-mode’s ability to execute source code within Org-mode documents. Babel started life as Org-babel, an extension to Org-mode. It was integrated into the Org-mode core at version 7.0. The author of Babel is Eric Schulte. The secondary author is Dan Davison.
List of supported languages with information on requirements, configuration instructions, and pointers to language specific documentation.
https://orgmode.org/worg/org-contrib/babel/intro.html
An online set of installation and setup instructions, as well as an overview of the main features of Babel, with plenty of examples.
A Multi-Language Computing Environment for Literate Programming and Reproducible Research
A journal paper providing the most up to date and complete introduction to using Org-mode and Babel for Reproducible research and literate programming.