[1] This book explores the question of nature versus nurture as it pertains to training for athletes in sports using anecdotes which favor both sides of the argument.

Epstein examines the argument that Kalenjin tend to have a body type conducive to distance running in part due to Allen's Rule.

Pitsiladis analyzes DNA in Jamaica, and finds no special signature that links maroons and sprinters, and concludes that the genetic evidence does not support the island folklore.

Rather, both Epstein and Pitsiladis place considerable emphasis on the popularity of the national high school track and field championships as part of the Jamaican sprint dynasty.

In chapter of the book, Epstein discusses problems with classifying athletes as simply "black," as he notes that there is more genetic diversity within Africa than in all of the rest of the world combined.