Eric S. Raymond

Eric Steven Raymond (born December 4, 1957), often referred to as ESR, is a computer programmer and open source software advocate. Author of Nethack Guidebook.

His name became known within the hacker culture when he became the maintainer of the "Jargon File". After the 1997 publication of important essay on programming "The Cathedral and the Bazaar", Raymond became, for a number of years, an informal representative of the open source movement.

based of extensive Wikipedia entry