The history of time is bound up with the history of synchronizing clocks. Without this synchronization, Modern societies can’t function. Galison tells the story of Einstein and Poincaré from the perspective of this electromagnetic problem of making sure that time can be coordinated across vast differences.

As the story unfolds, it’s quite clear that for both men, thinking about the relativity of time was not merely an abstract undertaking. It was tied into the practical problems of making a Modern society tick.