For the target audience, you probably can't go wrong with Bob LeVitus' Mac OS X Panther For Dummies book. It's current and I saw a favorable review on TidBITS or one of those sites not log ago.

My father has been using a PC since 1999. He is relatively well versed in computers and can make his way around them o.k. He knows more than basic terminology and how to fix minor problems. He, ...