There is no class system in Skyrim, they took that out.

You have races with perks like before, but in Skyrim there are constillations that you navigate which are basically perk trees, you pick what you want based on your skill lvl and what you have unlocked on the tree prior.

Its a step in the right direction, you get the complexity of building a class, but there is so much flexibility that you can really make some nice customized character types or have a jack of all trades and not feel weak on any front.