There was excited chatter as the revolutionaries met in a nondescript garage in Menlo Park, California, but in the beginning few of them really knew how they would change the world.

And yet within a year of that first meeting of the Homebrew Computer Club on March 5th, 1975, a computer was in the hands of consumers for just a few hundred dollars and the personal computer revolution was under way.

Steve Wozniak says that meeting inspired him to design and build the first Apple computer, but he almost didn't show up. "I was shy and felt that I knew little about the newest developments in computers," he says.

Shyness is a theme for Wozniak. He is "the other Steve" in the duo behind Apple Computer - the self-effacing engineer to Steve Jobs's brash marketing whiz.

While Jobs, now presiding over the success of Apple's iPod, is almost a household name, the other Steve has been content to stay out of the limelight, until now.

In a book titled iWoz published this week, Wozniak seeks to tell the engineer's side of the story and set a few things in the record straight.

For him, the day that defined the personal computer was June 29th, 1975, the first time he typed a character on a keyboard and saw it show up on the screen right in front of him. "Every computer before the 'Apple I' had that front panel of switches and lights. Every computer since has had a keyboard and a screen," he writes.

Wozniak, variously known as "Woz" and the "Wizard of Woz", put together circuit boards for what would be called the Apple I, and Jobs sold them for $500 (€393) each to a new computer store, the Byte Shop, in Mountain View, California. "There are stories that Steve [ Jobs] and I engineered those first computers together," he writes. "I did them alone."

By 1977, the pair had introduced the Apple II, still recognisable as a personal computer even today, and sold two million by the time it was superseded by the Macintosh. As Apple grew, Wozniak shunned management positions and worked in a cubicle alongside other engineers, even though he was a co-founder.

An incident that still grates is the way his departure from Apple in 1985 was reported in the press. The fact that he was unhappy with the way Apple was going was not a factor, he said, and he left solely so he could start his own company.

He is still on the payroll of Apple and sometimes represents the company at events.

He also still counts Jobs among his friends and, in an interview, said that any differences between them were very minor and a "little bit misinterpreted".

His book describes their long friendship, including a controversy over a fee for a game called Breakout in the early days and another incident in which Jobs blocked a design company from working with Wozniak.

Wozniak said that Jobs declined to write a foreword for the book. A spokesman for Apple declined to comment.

The book's title, iWoz, invites comparison with Jobs, who has sometimes called himself "iCEO" since his returned to Apple as interim chief executive in 1997.

Wozniak, a bear of a man at 55, retains the innocence of the computer nerd who in 1975 was too shy to talk at computer club meetings. In fact, he never seemed to aspire to massive wealth.

Along the way, he has taught at a public school and spent millions of dollars of his own money to fund rock concerts.

And he sold stock cheaply to other Apple engineers before the company's successful initial public offering in 1980 so that they could share in the wealth.

From his experience, he advises today's would-be inventors to avoid big, structured companies, where there is less leeway to turn clever ideas into revolutionary new products.

"Yes, a person who is technical, a little bit nerdy, not so social, can just do some common-sense things and have it work out great," he said.