Born and raised in San Jose, California, Wozniak designed his first computer at age thirteen. He credited his father, an electrical engineer; Tom Swift books (a series about a young inventor); and local science fairs with encouraging his interests in electronics.

In high school, Wozniak met Steve Jobs, who shared his enthusiasm for electronics, and they soon became friends. In 1971, they assembled and sold "blue boxes," an illegal device used to make long-distance telephone calls without being charged. After dropping out of college, Wozniak began designing calculators at Hewlett-Packard, and Jobs gained employment at Atari, the video game company. They stayed in touch, though, and Wozniak, at Jobs's request of Jobs, designed a new game for Atari called "Breakout," which earned him $750.

In 1975, the two friends joined the Homebrew Computer Club (an informal information exchange group for computer enthusiasts based in Menlo Park, California). When the club displayed...