2600: The Hacker Quarterly is an American seasonal publication of technical information and articles, many of which are written and submitted by the readership, on a variety of subjects including hacking, telephone switching systems, Internet protocols and services, as well as general news concerning the computer underground.

[1][2] The magazine's name comes from the phreaker discovery in the 1960s that the transmission of a 2600 hertz tone – which could be produced perfectly with a plastic toy whistle given away free with Cap'n Crunch cereal, discovered by friends of John Draper – over a long-distance trunk connection gained access to operator mode, and allowed the user to explore aspects of the telephone system that were not otherwise accessible.

[citation needed] The magazine traces its origins to early Bulletin Board Systems as a place for hackers to share information and stories with each other.

It is published and edited by its co-founder Emmanuel Goldstein (a pen name of Corley which is an allusion to George Orwell's Nineteen Eighty-Four) and his company 2600 Enterprises, Inc.[6] 2600 is released on the first Friday of the month following a season change, usually January, April, July, and October.

Both shows can be downloaded or streamed via the 2600 site, and are also broadcast on various radio stations: In the 1995 movie Hackers, a character named Emmanuel Goldstein, also known as "Cereal Killer", was portrayed by Matthew Lillard.