Jorn Jørn Lorentzen Cracking Service - a Danish cracker from about 1987 until 1992(?). Cracked many games, about 120.
He wrote a few tools, including the [[JL-COPY]] suite of file and disc copying utilities, and also wrote a [[JLCS Demo|demo]]. He was made infamous by [[NWC]]'s [[Kill JL]] demo.
Jørn Lorentzen is also the author of the Danish book [[Maskinkode med Amstrad]].