The beginning of the book is about the biblical David vs. Goliath story, and it exposes some myths we hold as a culture about what it means to be an underdog and potentially how wrong we are about the balance of power. Gladwell points out some important ways in which underdogs routinely are more powerful and skilled than their giant opponents.
However, that's pretty much where the title theme of the book stops, as I found the rest of it to be a lot more about overcoming difficulties and how "desirable difficulties," like mid-sized classrooms, dyslexia, and childhood bereavement can actually make people stronger and much more accomplished.
Each of the book's chapters focuses on a few specific people's lives, and these stories, taken from different points in history, show various ways in which people over time responded to similar difficulties. I liked how all the major parts of the book built on each other in this regard. The main evidence of the book comes from research studies and the many interviews that the author conducted with the main characters of the stories he recounts.
I wondered a lot about how the ideas of unexpected strengths and weakness can apply to the world of start-up Davids vs. big company Goliaths. What are the strengths and weaknesses that we traditionally ascribe to each but which might indeed be backwards?
I definitely recommend this book to anyone who likes Gladwell's other writing and especially people interested in education, criminal law, learning disorders, and history.