1938- American author and counter cultural gadfly. Graduated from Stanford in 1960 with a degree in Biology. He was one of the menbers of Ken Kesey's Merry Pranksters. Probably most famous for founding, editing and publishing the Whole Earth Catalog from 1968 to 1985 and it's offshoot the Co-Evolution Quarterly which later became the Whole Earth Review. He was one of the very early Journalists to see the emergence of the computer culture. He wrote an article in the Rolling Stone in 1972 titled, "Fanatic Life and Symbolic Death Among the Computer Bums". In that article he described students in universities around the US who played a computer game that spanned all the mainframes together. They were thus able to play in the same virtual space.
He attempted to publish the ill fated "Whole Earth Software Catalog" but it seemed the industry was moving way too fast to really take a meaningful snapshot of it. During that time, he organized the first "Hacker's Conference". Which is an annual event that continues to this day.
In 1984 he founded The Well or Whole Earth Lectronic Link. It was the bigget of pioneering "online communities" which used a mini computer as it's host. It still exists today.
In 1986 he went to the MIT Media Lab as visiting scientist and he later wrote a book about it: The Media Lab: Inventing the Future at MIT (1987). He is a member of the board of Directors of the Electronic Frontier Foundation (EFF).
He also wrote a book called, "How Buildings Learn: What Happens After They're Built 1994". The following year he co-founded, along with Danny Hillis, The Long Now Foundation whose core project is the construction of a 10,000 year clock called The Clock of the Long Now. In 1999, he wrote a book about it: The Clock of the Long Now: Time and Responsibility.
Sources: my own reading, I read "Fanatic Life..", Media Lab, many issues of Whole Earth Review and was a member of the WELL. I also referenced Stewart's online resume.