Thanks, Dave! That's very helpful and interesting about the difference between the valet key and the master key. The master key the locksmith made also works on the passenger side door. (Actually they work better on that door because the driver's door lock was affected by an accident.) The trunk key is shorter than the other.

Though I'm not the original owner, I do have the owner's manual. I don't have the original keys, nor as far as I know do I have the little metal tag with the key code number.

The owner's manual says to to write the key code number in the front of the manual. Though the original owner was very conscientious about scheduled maintenance, he didn't write the key code number in the manual.

So if I were to have another key made, it looks like I should either try to use the VIN and contact Volvo, or have a locksmith do it the same way they did before.

My key is only very slightly twisted, so I worry that the main problem may be with the lock. My mechanic also hoped the problem was with the key because, as he said, "the lock is obsolete." Ouch.

On the positive side, the key & ignition have behaved themselves since Tuesday. I think the mechanic put some lock lubricant in the lock, which may have helped.

Thanks again!