From the abstract:
Computer networks and the applications that run on them are growing in size and complexity at an ever faster rate. Managing their configuration by hand became intractable long ago. Various schemes have been devised by systems administrators from all over the world to ease this burden. These usually manifest themselves as a mess of duct tape scripts wrapped around complex change management policies. There is a better way.
In this presentation, I will cover the history and evolution of configuration management strategies, as well as the concepts that power modern configuration management frameworks like Opscode Chef.