Santa Lives! (2005)

More than a half century ago in his book Mere Christianity, C.S. Lewis affirmed his place as one of the world's great religious thinkers by making a case for God's existence. Now former Spy writer and self-proclaimed ''santologist'' Ellis Weiner sets out to do the same for Kriss Kringle in Santa Lives!, a merrily eccentric volume, jam-packed with philosophical principles as varied as Occam's razor (the simplest explanation is usually best) and the Argument from Truism (it involves Dean Martin lyrics). Perfect for the cynic on your list.