Harvard’s Lepore and Christensen disagree on the importance of disruptive innovation. But debating whether companies survived or prospered during times of change cannot settle it. The four driving forces of industry disruption are changes in technology, policy, business models, and user dynamics. The forces interrelate. Technology emerges at an accelerating pace—but some of it fails, not because it is better or worse, but by lack of user enthusiasm or because the business model was not well thought out. On the policy side, the genetic testing company 23andMe got slapped from FDA and had to halt marketing its core product, despite public enthusiasm for its technology. Is it possible to lead in all four aspects? Innovation only gets interesting when we get into the nuts and bolts.