David Epstein isn't a scientist, but a sports journalist, who has made a long learning journey to be able to write about so technical subject. I believe this book is better, when it's written by a journalist and not by a scientist. Book goes quite deep into the genes and biology, so it's better when it's written in bit more understandable way.
Book tells stories and facts about athletics, basketball, sprint running, long distance running, cross country skiing, baseball and many others. It really tries to look for patterns behind athletes and their genes. For certain sports there are definitely genetic differences that make some athletes to have a superior change to succeed to others. Still success always needs lots of training.
In one way book is depressing for some sports. As an example, with current conditions in the world Kalenjin Kenyans will rule the marathon and long distance running field for some time. But actually not that long ago, Finnish people used to rule the long distance world (Hannes Kolehmainen, Paavo Nurmi, Lasse Viren) , before we got richer and didn't run that much anymore. So in a way we Finns still might have the genes for it, but our environment and training doesn't support those anymore. The same might happen to the Kenyans at some in the future.
The whole book bounces between nature and nurture. What is certain is that there are no genetically perfect athletes, because no one doesn't have any good ideas what genes actually are needed for which sports. There are some genes found which might prevent success in some sports and some genes that are common with the elite athletes in that sport. Most often still, the genes of elite athletes can be found from thousands of other who still are not elite. So there is no one answer for nature vs nurture debate.
One other thing that interested me was the trainability of people. Different genes actually mean that people develop differently. Populist journalism often tells that training like this and that will only give results. The fact is, people acquire skills differently. The famous 10 000 hour rule, isn't exactly true, but then on the other hand it gives an idea of the ball park people need to train. People need to train the way their body and mind adapts. That's the most important lesson of the book.
I highly recommend this book the everyone interested about sport training or coaching. It felt bit longish at some point, but reading this is time well invested.
Written by +Henri Hämäläinen