The Internet has revolutionized economies and societies much as electricity and the chemical industry did a century ago and the steam engine and railroads did nearly two centuries ago. How did it come about? Greenstein has crafted a detailed history of the Internet, which began as a U.S. Department of Defense project in the 1960s, later moved to the National Science Foundation, and was ultimately turned over to the private sector in the early 1990s. Two early strategic decisions encouraged tremendous innovation “at the edges,” as the author puts it: the use of the “packet switching protocol,” which allows networks to transmit massive amounts of data efficiently, and the development of the “end-to-end principle,” which dictates that critical Internet nodes transmit information without altering or controlling it—a development that would not have occurred if AT&T had continued to dominate U.S. telecommunications, as it did for decades prior to 1984, when the so-called Bell System was broken up. Some governments regret the resulting freewheeling nature of the Internet and wish to exercise greater control over it, which pits them against a large community of Internet providers, users, and activists who subscribe to a form of technological libertarianism.