If Steve Jobs was the public face of Apple, then Steve Wozniak—the inventor of the first personal computer and co-founder of what would become one of the world's most popular companies—was surely the soul of the company.

After all, it was Wozniak (known familiarly as "Woz") who once said, "I designed the Apple I [PC] because I wanted to give it away for free to other people."

Though he would eventually become rich and famous (though never on a Jobsian scale), Woz was never in it for the money or the prestige.

As he explains in his autobiography, iWoz, his lifelong ambition was to become an engineer's engineer, a passion his father, an engineer at Lockheed, helped to inflame by encouraging his son at each step along the way.

"[My father] told me that as an engineer, you can change your world and change the way of life for lots and lots of people," Woz remembers. "To this day, I still believe engineers are among the key people in the world."

Another early influence was Tom Swift Jr., the do-gooder boy hero of an eponymous series of science fiction books who saved the planet time and again by inventing some kind of gadget or gizmo, motivated solely by a desire to do something good for people—which became Woz's motivation as well.

[My father] told me that as an engineer, you can change your world and change the way of life for lots and lots of people. To this day, I still believe engineers are among the key people in the world."
—Steve Wozniak

As has become legendary in Silicon Valley lore, Woz and Jobs met in the garage of a mutual friend and bonded over their shared love of Bob Dylan's music, pulling pranks, and, of course, electronics.

The two kept in touch over the years, in particular at regular meetings of the Homebrew Computer Club, whose members got an early look at Woz's latest project—a personal computer with a screen and a keyboard, the first of its kind. In his spare time, Woz developed the hardware, designed the printed circuit board and the operating system, basically creating on his own the archetype of all personal computers to follow.

Jobs saw Woz's fledgling PC as more than just a part-time project, and he recruited Ron Wayne (like Jobs, an employee of Atari) to team up with Woz in 1976 to form a company, Apple Computer, to sell the new gadget. Woz was working for Hewlett-Packard at the time, and famously, HP turned down the offer to pursue further development of the embryonic PC.

The Apple I was a very modest success, as Jobs targeted it to the then-small but passionate hobbyist market. The Apple II, however, which Woz built from the ground up while moonlighting from his day job at HP, would become a computer for "regular people in regular homes."

Agreeing to join Apple full-time only if he could stay an engineer and not get into management, Woz soon became one of the most famous engineers of all time when the Apple II, "more than any other machine, launched the personal computer industry," according to Walter Isaacson, Jobs' biographer. Roughly six million units were sold.

Wozniak would eventually leave Apple in 1987 (though remaining on the payroll), and in the years since he has launched several high-tech companies, organized a couple rock music festivals, taught school and funded a number of philanthropic organizations. He was inducted into the National Inventors Hall of Fame in 2000.