The American Telephone and Telegraph company—better known as AT&T—and the telephone are virtually synonymous. Both the company and invention which made it famous hold lofty positions in American history. AT&T was the largest corporation in the world for much of the twentieth century, employing over one million people. At the time of its court-mandated breakup in 1984, the company's assets totaled $155 billion, more than General Motors, Mobil, and Exxon combined. The telephone's impact is harder to calculate, but it played a major role in the rise of the modern corporation, served as a symbol of American ingenuity and power, and continues to connect people worldwide.

The parent company of the Bell System, commonly referred to as "Ma Bell," AT&T was a government-regulated monopoly for much of its existence. Federal and state officials allowed AT&T to have monopolistic control over...