What can the son and brother of a president, grandson of a senator, and great grandson of the founder of the Walker Cup have in common with the son of a failed Kenyan politician? Look beyond the biography to the psychology.

Unlike his more guarded elder brother, Jeb Bush talks openly and candidly about himself. Of course, there are limits to candor. Jeb Bush has spent almost all of the past 20-plus years either in public office or in pursuit of it. He understands self-presentation and is adept at it: There is artfulness in his artlessness.

Yet when a man speaks for the record as often as has Jeb Bush, he deposits there enough material to learn something interesting about the man he is, rather than the boy he was.