We usually imagine that invention occurs in a flash, with a eureka moment that leads an inventor towards a startling epiphany. In truth, large leaps forward in technology rarely have a precise point of origin. At the start, forces that precede an invention merely begin to align, often imperceptibly, as a group of people or ideas converge, until over the course of months or years (or decades) they gain clarity and momentum and the help of additional ideas and actors.

—Jon Gertner