10-year old is the right time.

Larry Gonick's "Cartoon History..." books.  His other "Cartoon..." books may also pique a child's interest, such as the one on probability.

The Perplexors from mindware.com. One question a day starting with the easiest, encourages him to think rather than to feel. Condition a cerebral reflex over a visceral one.

Children's version of the Bible for his reading level. Intelligence and wisdom are not the same thing.