What constitutes an official job offer

[cyclistca]

I'm presently interviewing with a company on the other side of the country. I'm very confident that they are going to make me an offer within the next two weeks. I'm wondering if an e-mail offer would be sufficient or should I ask for a written offer?

 

[gittyup]

An official offer will come on paper. Mine came via FedEx...

 

[rseraji]

I think an official offer is needed for both parties to sign and return..