We know a noun has pervaded our sensibilities when we derive a verb from it. “Network” appears in 16th century English, and was meant literally: a work of netting, coarse or fine. As an abstraction meaning any complex design of threadlike entities, from a river system to a political economy, the word didn’t arrive until the early 19th century. Samuel Taylor Coleridge and Ralph Waldo Emerson were among the early adopters—writers influenced by European Enlightenment thought, especially as filtered through German thinkers. “Networking” as a verb appeared in our own time, with the computerization of everything serving as an accelerant.

Niall Ferguson does exactly what historians should do, explaining the origins of the modern understanding of networks and illustrating the theory with several dozens examples, ranging from Italian Renaissance merchants and Spanish explorers to the election campaign of Donald Trump. The main title of The Square and the Tower: Networks and Power, from the Freemasons to Facebook refers to the city center of Siena, Italy where the shadow of the watchtower falls on the marketplace below. The tower represents the “vertical” or hierarchic structure, the square the “horizontal” or democratic structure. The one tends toward rigidity and command, the other toward fluidity (at times anarchy) and consent. Ferguson notes that the tension between these two kinds of “networking” is “as old as humanity itself,” and sees history as the interplay of the one with the other.

Perennial and universal phenomena like networks must have attracted the attention of intelligent people long before the word was coined. Signor Machiavelli inaugurated “modernity” as the human quest to master the course of events and to gain control over that vast network, nature; the centralized modern state he lauded exemplifies the “vertical” network, and he intended it to be an indispensable part of his project to out-“network” the biggest network.

Before Machiavelli, the earliest philosophers, in naming “nature,” marked out an order of regularly interacting parts, a “whole.” Turning to human life, they did not imagine “states” but instead identified regimes—effectively, networks of rule involving persons and their institutions, their patterns of life, and the purposes those persons, institutions, and social patterns aimed at achieving. Those philosophers understood politics as the architectonic art, the political community as the most comprehensive form of human organization.

Ferguson identifies the intellectual founder of modern network theory as the influential Swiss-born mathematician Leonard Euler, who formulated it in 1735 while working in the Imperial Russian Academy of Sciences. He later joined the Berlin Academy, so his two major political patrons were no less a pair of enlightened despots than Peter the Great and Frederick the Great, sitting atop hierarchic networks that enabled Euler’s theory to circulate far, wide, and rapidly.

Euler studied a set of seven bridges in the Prussian city of Königsburg. Why was it impossible, he wanted to know, to walk across all seven bridges in one trip, without re-crossing any of them?

The geometrician’s answer involved understanding the relations of the bridges as a pattern of lines and their intersection points or “nodes.” The pattern or structure of any given set of lines and nodes delimits ways in which energy (in the case of the footbridges, the flow of pedestrians) can travel—as in one of today’s power grids, for example.

Euler was among the pioneers of calculus, the branch of mathematics which takes the classical plane geometry of Euclid and in effect “sets it in motion,” plotting points along a curve—this, much to the fascination of later political philosophers, as they considered both the modern state (the “tower”) and its civil wars (in the “square”). Americans will recall their friendly visitor, Alexis de Tocqueville, who described both the “tower” of administrative despotism and the “square” of democratic associations as both complementary and conflicting features of modern life.

The attempt to reduce a social network and the changes it undergoes to a mathematically-based science awaited the invention of the modern, French- and German-inspired academic discipline of sociology toward the end of the 19th century. As the theory developed, writes Ferguson, several insights accrued.

First (and pace Thomas Friedman), even the most “democratic” networks aren’t quite “flat,” horizontally arranged though they may be. Persons located at the nodes where social, political, and economic lines cross enjoy an advantage over persons who aren’t. “Sometimes, as in the case of the American Revolution, crucial roles turn out to have been played by people who were not leaders but connectors,” he says. Whereas he holds up midnight-riding Paul Revere as his example, I would choose Benjamin Franklin, that supreme networker of both “tower” and “square.”

Second, consent-based networks organize according to the principle of “homophily,” a notion more colloquially captured in the old saw, “Birds of a feather flock together”—a principle now playing on a website near you, and in clubs, churches, and political parties for millennia.

Third, and paradoxically, weak ties with a network are strong. The stronger my ties, the more exclusive they are, and the more exclusive my ties, the less extensive they are. This point obviously needs to be supplemented by the observation Ferguson made initially, that certain positions or “nodes” within networks are better than others; a tightknit group occupying a “node”  might extract considerable benefits and hold on to its position for a long time. This accounts for a fact well known to politicians and political scientists alike, which is that oligarchies are hard to overturn—good news for the Chinese Communist Party.

Fourth, when we speak of an image or a message “going viral”—whether it’s Hitlerian poison circulating through the veins of Germany or a Youtube photo of kittens in a basket—the structure of the network delivering the message matters more than the message itself. Marshall McLuhan’s phrase, “the medium is the message” (which itself went viral, half a century back), succinctly summed up the thought. Grant Wood’s career as a painter went nowhere until he hired an agent with “connections”—connections to a network. Or, to take one of Ferguson’s examples, “Without Gutenberg, Luther might have been just another heretic whom the Church burned at the stake.”

Another stock phrase, “The city never sleeps,” applies to networks (all of them, not only urban ones). Even the more rigid, hierarchic networks—trees, monarchies—stay active, change over time, cause things to circulate, so long as they live. Peter and Frederick were not only great; they made things happen by establishing structures, including research and educational institutions, militaries, railways systems.

Networks also interact with other networks. This gets dramatic when a hierarchic network confronts a newer and more egalitarian one. “When a network disrupts an ossified hierarchy it can overthrow it with breathtaking speed,” as communist parties in Central and Eastern Europe learned to their sorrow. “But when a hierarchy attacks a fragile network, the result can be the network’s collapse”; not all bands of guerrilla fighters win their wars of attrition.

Finally, the networked rich really do get richer. “Most social networks are profoundly inegalitarian” given their position along the node-and-line structure of “horizontal” networks. The medieval churchman, the Gilded Age railroad magnate, and even the studiously egalitarian computer entrepreneurs of Silicon Valley, got very rich, sometimes very quickly, by occupying strategic chokepoints in the structures they knew so well, having invented them.

All of this means that the much-ridiculed conspiracy theorists among us are on to something, even if they don’t quite know what it is. Ferguson shows how such organizations as the Illuminati and the Freemasons did indeed conspire in their semi-secret networks. In describing  exactly who they were, how they operated, and to what extent they succeeded (usually much less than their enemies suppose), he both confirms and sanitizes—makes sane—parts of conspiracy theorists’ hypotheses. It turns out that, contrary to certain dyspeptic members of the monarchist clergy of France, the Freemasons didn’t really cause the French Revolution—but they did have a hand in it. The most successful network of conspirators in Western history was surely the early Christian Church, to the consternation of pagan-minded observers from the Roman Emperors to Edward Gibbon.

Much of the entertaining instruction in the book comes when Ferguson gets down to cases that illustrate network theory. Born in Scotland, he is one of those charming know-it-all show-offs in the Oscar Wilde line, albeit with fewer witticisms and more facts, as I suppose one must expect from a historian. Not surprisingly, one of his cases is the British Empire, and the way in which  the British elite prospered by exercising a “relatively light touch” in ruling Britain’s colonies (American Revolution =  lesson learned). By the middle of the 19th century, the Empire rested in large measure on local rulers and such “private networks” as steamship and telegraph companies, banks, and missionaries. To be sure, the elitists themselves doubled down on snobbery and old-school ties, but they also proved amenable to marrying vigorous and attractive outsiders—even the occasional American such as Jennie Churchill. They still hunted foxes, but condescended to sit with tradesmen on corporate boards and to write for newspapers.

Networks can also fail catastrophically. Designed in 1814, under the Peace of Vienna, to prevent recurrence of anything like the Napoleonic wars, the European geopolitical order solemnized under that pact held firm for three generations thanks to a well-founded aversion to death and destruction. By the time Otto von Bismarck had prodded the many Germanies into consolidating as one state (a state that could whip France), patchwork on that order was urgently needed.

With his Russian diplomatic counterpart Nikolay Girs, Bismarck then designed the Secret Reinsurance Treaty of 1887. Under its terms, “Germany and Russia each agreed to observe neutrality should the other be involved in a war with a third country, unless Germany attacked France or Russia attacked Austria-Hungary.” Russia was thus blocked from allying with France to contain Germany, but the benefit was Russia’s gaining a free hand over the Black Sea Straits. The arrangement dissolved after the preening, over-ambitious fool of a young Kaiser, Wilhelm II, got rid of the troublesome old Bismarck and failed to honor the 1887 treaty. After that, “the surprising thing” was not that war “happened in 1914, but that it did not happen sooner.”

The Great War itself led to another German networking blunder: sending an obscure conspiratorial networker named V.I. Lenin from confinement in Germany, where he belonged, back to his native Russia, along with $12 million of walking-around money. “To an extent most accounts still underrate,” writes Ferguson, “the Bolshevik Revolution was a German-financed operation,” one that took Russia out of the Great War only to plunge it into decades of internecine, state-sponsored terror. The Gulag, after all, was in one sense yet another network, as were the spy cells Josef Stalin established at Cambridge University and in Washington, D.C.

This brings up an important difference between network theory and classical regime theory. Networks, studied as mathematicians like Euler and mathematizing social scientists study them, are “value-neutral,” mere structures, whose causal importance outweighs the effects of the ideas and sentiments they convey. A suspicion nags, however: The medium may be the message, but so is the message. The various messages I receive come to me through the same medium, my computer, but some of the messages warrant serious attention, others not.

What is more, a message might shape a medium, as a visit to a Gothic cathedral will suggest. When Aristotle contemplates a network, he does not rate the structure of the tree, or the city, above the way they live or the purposes they pursue (even if, in the case of the tree, the organism has no consciousness of its purpose, or at least none a human can do much more than imagine). As a latter-day Aristotelian once said, ideas have consequences, too—consequences that are to some degree independent of, even while entwined with, structures, persons, and customs.