My favorite "how it works" article is The Git Parable
http://tom.preston-werner.com/2009/05/19/the-git-parable.htm...
http://tom.preston-werner.com/2009/05/19/the-git-parable.htm...
> you can only really use Git if you understand how Git works. Merely memorizing which commands you should run at what times will work in the short run, but it’s only a matter of time before you get stuck or, worse, break something.
Not exactly a 'how it works' article, more how it can work really well