Wizards Presents: Races and Classes

I think it was a pretty good write-up to showcase the thought process and the design iterations that occurred to bring us the 4th Edition (obviously, I read it pretty late; just following up on 4th Edition though I don't play anymore). Sure, you might not agree with some of the decisions made, but overall, it was well-written and an interesting preview or introduction of the 4th Edition. It's obviously not a RPG sourcebook, but more like an appetiser to get people interested in 4th Edition.