This non-fiction selection is really a discussion about the art of winning (success). The author starts with a description and analysis of the original (Biblical) "battle" between David and Goliath. The author hypothesizes that, seemingly weaker David, won over the giant (in physical respects) Goliath because quite actually, he used his already demonstrated skill to slay an opponent who was ill matched against his skill as a stone thrower. (Note: the author shares that in that age, skilled stone throwers were highly regarded in battle). One might take exception to his analysis of the "reason" for the win (i.e. he gives little weight to God's plans and purposes), but we get the point as a set up for the book's discussion relative to the modern age.
Gladwell uses multiple real life examples of people who might have had disadvantages, weaknesses or even disabilities, but went on to excel despite, often considered by others, "handicapping" conditions. For example, he discusses a flamboyant, highly successful prosecuting attorney born with dyslexia, who rather than being well prepared by reading all court documents, instead honed an exceptional ability to listen and attend to non verbals of communication to win cases.
He continues with other researched "challenges" i.e. the trauma of war, parent abandonment, an examination of the myth of class size in schools and the civil rights movement. He illustrates through many examples, how "we shall overcome" is possible when people examine their (and their opponents) weaknesses, strengths and determine to use both as part of their personal arsenal to get ahead.
Gladwell, encourages us to believe that rather than subscribing to the notion that, "nice guys finish last", nice guys (and girls) can come out a winner. With personal insight, perseverance and understanding weaknesses in a situation, and going around them i.e. finding another way, you too can come out a winner and be successful in your pursuits.