The problem with the Four Horsemen books is that they deliberately set out to attack the notion of a god or gods. That's immediately going to be a turnoff for most believers.

I personally recommend Carl Sagan's The Demon-Haunted World: Science as a Candle in the Dark, as while it only tangentially tackles the problem of gods and afterlives, it shows how to use the scientific method to see through hokum, dogma, logical fallacies and outright lies. More a case of leading a horse to water than forcing it to drink.