David vs. Goliath is about how the underdog is not at the perceived disadvantage when entering or dealing with a hard situation. Gladwell goes through a bunch of stories where our preconceived notions are wrong and actually hurt our decision making abilities and mask what we see at the outcome. His best example is the title of the book. Our preconceived notions are that Goliath is going to easily destroy this small soldier, David. We regard David, the lone opponent who stepped forward as stupid or insane because he was pitting himself against a veritable giant. What Gladwell shows it that David was very aware of his decision and made it knowing he was actually at the advantage because he was a slinger and not a hand to hand combat solider. Gladwell layers this argument on top of the argument about the health status of Goliath which added to his disadvantage but still David actually has the upper hand even without Goliath’s health problems.