Apart from the Macintosh, iMac, iTunes, iPod, iPhone and iPad, Steve Jobs was also known for his signature dressing style.

He was hardly ever seen without his trademark black turtleneck, blue jeans and gray New Balance sneakers.

According to biographer Walter Isaacson, Jobs would have been well-stocked with the black turtlenecks had he lived longer. His turtleneck made him the most recognizably attired CEO in the world.

People have wondered why Jobs always wore such unusual attire while unveiling revolutionary products. But there is a story behind the black turtleneck and blue jeans, which will be revealed with the release of Isaacson's authorized biography, Steve Jobs.

Isaacson spent more than two years conducting 40 exclusive and unprecedented interviews with Jobs and his family members, friends, adversaries, competitors and colleagues for the book.

Jobs had explained his signature dressing style to Isaacson in an interview.

The author sent an excerpt of a particular passage from his book to the Web site Gawker which it published Tuesday:

On a trip to Japan in the early 1980s, Jobs asked Sony's Chairman Akio Morita why everyone in the company's factories wore uniforms. He told Jobs that after the war, no one had any clothes, and companies like Sony had to give their workers something to wear each day. Over the years, the uniforms developed their own signature styles, especially at companies such as Sony, and it became a way of bonding workers to the company. 'I decided that I wanted that type of bonding for Apple,' Jobs recalled.

Sony, with its appreciation for style, had gotten the famous designer Issey Miyake to create its uniform. It was a jacket made of rip-stop nylon with sleeves that could unzip to make it a vest. So Jobs called Miyake and asked him to design a vest for Apple. Jobs recalled, 'I came back with some samples and told everyone it would great if we would all wear these vests. Oh man, did I get booed off the stage. Everybody hated the idea.'

In the process, however, he became friends with Miyake and would visit him regularly. He also came to like the idea of having a uniform for himself, both because of its daily convenience (the rationale he claimed) and its ability to convey a signature style. 'So I asked Issey to make me some of his black turtlenecks that I liked, and he made me like a hundred of them.'

Jobs noticed my surprise when he told this story, so he showed them stacked up in the closet. 'That's what I wear,' he said. 'I have enough to last for the rest of my life.'

Isaacson's book is due to be released in two weeks.

Must Read : Steve Jobs Biopic Coming Soon: Will it Become a Blockbuster like Apple Products?