I've had the good fortune to meet Jim Weirich and see him speak at several conferences. He's a very funny guy, and deeply smart. (One of his slides last year, while discussing the genesis of the tool, had the innocuous title "How hard could it be?", meaning how hard to make a general purpose state machine to do system automation things in Ruby. Here's a transcript of an interview that might give you some further insights. And you really do want to find out more about Make, too.
http://www.infoq.com/interviews/jim-weirich-discusses-rake
Walter