WordPress/book — pull request #19 by smckeown (2013-08-23 14:55:44+00:00)
Title: First draft of Chapter 4

A first draft of chapter 4 which deals with the history of the GPL and
free software foundation, discusses the freedoms of the GPL, copyleft,
and the difference between permissive and copy licenses. Also, why the
GPL is important, and how the GPL came to be WordPress' license.