Statement of Purpose A.K.A. the who what now?

[McTahr]

So, I'm looking at a whole lot of grad school applications, and they have this one section I haven't filled out yet that says "Statement of Purpose" and expects me to like, type words and shit and be all personable.

And of course, I could hop in my googlecopter and fly over the intertubes to web me up a respectable answer as to just what all that entails and the best way to go about it.

But I'd rather hear from the peanut gallery.

So, suggestions?

I know what it is, in the sense that I know where China is. Like, I could find it on a globe, but ask me to busk out some directions and you're going to get a hand-drawn picture of you eating a cock or three.