In the introduction to Outliers, Malcolm Gladwell tells the story of Roseto, a small town in Pennsylvania. In the late nineteenth century, Roseto became the object of scientific study because the people there enjoyed exceptionally good health and normally lived to an advanced age. Scientists analyzed the diets, exercise regimes, and various other aspects of the lives of individuals in Roseto, but could find nothing to account for their unusual health and longevity.

Finally, a doctor called Stewart Wolf proposed a cultural and communal explanation. Wolf noted that the lifestyle of Roseto's inhabitants was similar to that in the area of Italy from which most of them had emigrated. They lived in extended families, with a friendly, mutually supportive community. Gladwell says that Wolf had found a solution by looking at the bigger picture rather than obsessing about the minutiae of what individual people in the community ate or how much they exercised. It was the unusual lifestyle of the Roseto community that made the town an outlier as far as the health of its inhabitants was concerned. Gladwell concludes the introduction by saying that he intends to apply Wolf's principles in the field of public health to determining why people and communities succeed in other areas of life.