Pidgin and creole languages - Salikoko Mufwene

This article by Salikoko Mufwene was published in the International Encyclopedia of the Social and Behavioral Sciences in 2002. It explains what are pidgin and creole languages, how a creole develop from a pidgin and the connection between creolization and linguistics development.
Salikoko Mufwene is a linguist, professor at University of Chicago.
In this article, Mufwene explains very directly the definition of pidgins, the main reasons it appears, and how it becomes a creole. It's not a very long article, and he dedicates most of it to talk about the process from the creation of a pidgin until it becomes a full grammatic language, with native speakers, and by that becomes a creole.

http://humanities.uchicago.edu/faculty/mufwene/pidginCreoleLanguage.html