From the worship of ancient Rome to the dynasties of the Renaissance, from the Founding Fathers of the nation to Facebook, the book chronicles the rise, fall, and resurgence of networks, showing how network theory—concepts like clustering, degrees of separation, weak ties, and transition phases—changes the way we understand the past and the present.

If The Evolution of Money placed Wall Street in historical perspective, The Square and the Tower does the same for Silicon Valley. It makes a bold prediction about which hierarchies will withstand this new wave of network disruption—and which will fall.

For the most part, history is hierarchical: it deals with emperors, presidents, prime ministers, and marshals; with states, armies, and companies; with top-down mandates. Even history "from below" typically concerns unions and labor parties. But is this because hierarchical institutions create the records upon which historians rely? Are we losing sight of the informal, much less studied social networks that are the true sources of power and forces of change?

The 21st century has been hailed as the Age of Networks. However, as Niall Ferguson argues here, networks have always been among us—from the structure of the brain to the food chain, from the family tree to Freemasonry. Throughout history, hierarchies established in high towers claimed to rule, but often real power was found lower down, in the town square.

For networks tend to innovate. And through networks, revolutionary ideas spread. The fact that conspiracy theorists enjoy fantasizing about such networks does not mean they do not exist.