A founder of the Electronic Frontier Foundation and a former lyricist for the Grateful Dead John Perry Barlow has died.

EFF said in statement that Barlow passed away early Wednesday morning in his sleep at age 70. The cause of death was not immediately known.

Barlow was known for his belief in cyber liberties and co-founded the EFF in 1990 to champion free expression and privacy online.

EFF says that Barlow, "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."

He also wrote lyrics for Grateful Dead songs including "Touch of Grey" and "Brown Eyed Woman," among dozens of others.