It really depends on the state where the car is located, and or titled. Some states don't provide a title for cars older than a certain year. If that is the case, make sure that the seller is willing to provide a notarized (in your presence) bill of sale. This will give you recourse in the event of a problem because the notary will request identification from both of you, and the guy won't be able to give you a bill of sale with a fake name on it. In some states, like PA, a title is absolute proof of ownership, and is mandatory. Without it, you can't do anything with the car, and you can actually get into trouble if you possess a car without a title. In the end, you need to satisfy the requirements of your government, while protecting yourself from buying a stolen vehicle.