His stringy brown hair and mesmerizing green eyes once inspired the computer trade publication LinuxWorld to describe him as "Rasputin-like." At times during his controversial career, Richard Stallman lived in his ninth-floor office at the Massachusetts Institute of Technology (MIT), surrounded by books, printouts, and a blinking computer terminal. But Wired magazine has declared him "one of the greatest programmers alive."

Stallman, recipient of a $240,000 MacArthur Foundation "genius" grant in 1990, authored principal parts of the GNU/Linux operating system, estimated at the turn of the millennium to have more than 10 million users worldwide. He also founded the GNU Project and is founding president of the non-profit Free Software Foundation.

Stallman was born in New York City, two years after UNIVAC I (the machine that started the modern era of general-purpose commercial computers) was completed for the U.S. Bureau of the Census. His passion for the computer first...