Matt Cutts is married to his job (and cats and wife). Matt is the head of the anti-spam team in Google.

He's probably one of the people that clammed down on some old "test" websites I set up years ago - and rightly so. Matt gives some highly useful advice here. I've highlighted some of the most important issues below:

SEO Basics - If you're new to SEO you should watch this Matt Cutts Discusses Webmaster Tools Matt Cutts Discusses Dupliate Content Matt Cutts Take On Fabricated Link Bait Trust Rank Explained by Matt Cutts Matt Cutts on Big Brand BlackHat Sites Interview with Matt Cutts

And here's some other relevant ones:

Danny Sullivan of Search Engine Land (Don't mention the shirt)