How would you describe Lewis's writing style?

Arguably the most important thing about Lewis' style as a writer is that he is always looking for a compelling story to tell. In both his books and his articles, he spends a great deal of time talking to people involved and searching for the most compelling ideas and stories that fit the narrative he comes up with. Sometimes this leads to people feeling like he does not quite cover a story or an idea perfectly. On the other hand, it very frequently leads to very easy to read, compelling writing that he has applied to a variety of complex and technical topics. His exhaustive research also makes it easier for the reader to trust his narrative style because it is generally very well informed and detailed.
This extends to the way that Lewis will address a topic like high-frequency trading or the way that baseball has come to depend heavily on statistical analysis. He finds a compelling story that will address the topic and uses the story (or stories) to make his points and exposition more compelling. By using the story of Billy Beane in Moneyball or Michael Oher in The Blind Side, he addresses the ideas of statistical analysis and the evolution of the left guard position in football in a dramatic and compelling fashion.