For understandable reasons, when we tell stories of tech**logical in**vation, we tend to focus on insight and even seeming clairvoyance?the people who can see the future before the rest of us. But there's a flip side to such farsightedness that shows up again and again in the history of in**vation: the blind spots, the possibilities that somehow escaped our field of vision but that, in retrospect, seem glaringly obvious.