Digital freedom fighter and founder of Electronic Frontier Foundation, who wrote lyrics for the Grateful Dead, died in his sleep

John Perry Barlow, “visionary” internet pioneer, press freedom advocate and Grateful Dead lyricist, has died aged 70.

Barlow was named as a Guardian “Open 20” fighter for internet freedom in 2012 because of his work to establish the Electronic Frontier Foundation (EFF), which defends online liberties. The organisation announced Barlowdied in his sleep on Wednesday morning.

EFF’s executive director Cindy Cohn said: “We will miss Barlow and his wisdom for decades to come, and he will always be an integral part of EFF.”

She said: “It is no exaggeration to say that major parts of the internet we all know and love today exist and thrive because of Barlow’s vision and leadership. He always saw the internet as a fundamental place of freedom, where voices long silenced can find an audience and people can connect with others regardless of physical distance.”

Facebook Twitter Pinterest John Perry Barlow in 1991. Photograph: Ann E. Yow-Dyson/Getty Images

In an apparent reference to Barlow’s idealistic early work, Cohn denied he was “a straw man for a kind of naive techno-utopianism that believed that the internet could solve all of humanity’s problems without causing any more”. She said Barlow understood that “new technology could create and empower evil as much as it could create and empower good” and he made a conscious decision to focus on the latter.

Barlow wrote extensively on the internet and digital world. Among the most well-known of his works was the Declaration of the Independence of Cyberspace, published in 1996.

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The staunchly libertarian document demanded governments to avoid interfering in the internet, which he referred to as “the new home of the mind”.

“I declare the global social space we are building to be naturally independent of the tyrannies you seek to impose on us,” he wrote. The article is regarded as highly influential on the ethos of the internet and Barlow stood by his words two decades on, despite accusations of naivety and the creeping encroachment of governments into the digital sphere.

Facebook Twitter Pinterest Whistleblower Edward Snowden participates in a video conversation with John Perry Barlow in 2014. Photograph: Richard Drew/AP

In addition to his work with the EFF, Barlow co-founded the Freedom of the Press Foundation in 2012, which works to support public interest journalism. He sat on the board of directors, along with whistleblower Edward Snowden and investigative reporter Glenn Greenwald.

The Foundation tweeted: “Rest in power, Barlow. The internet will never be the same without you.

Outside of his activism, Barlow was good friends with Grateful Dead guitarist Bob Weir. The pair were the creative minds behind some of the psychedelic rock group’s most well-known songs, including Black Throated Wind, Mexicali Blues and Looks Like Rain.