While the content of the book is one interesting aspect, the way it was created and is being disseminated is also fascinating. It was a collective effort of econ professors from around the world, who all teach a localized version of the materials. They hired a company from south africa, to develop an open publishing platform. The goal is to turn markdown content into a number of outputs, ranging from a Oxford University Press textbook to a responsive static web site. Most of the tools are open source and all of the core content is on github. (Disclosure: I provided some input to the CORE leadership when they were starting to think about an open platform).