Sun Of The Sleepless is a black metal/ambient project of Ulf Theodor Schwadorf (aka Markus Stock) of Empyrium and Noekk fame.

The first release under this name was pretty standard black metal/ambient fare, having Ulf playing all instruments and doing the vocals. With the release of Tausend Kalte Winter, Sun of the Sleepless saw a change toward a more experimental side, with Ulf using an electronic beat instead of normal drumming for the title track. He further explored this style by releasing a full-blown trip-hop song called Neunter November in a compilation album.

In 2004, Sun of the Sleepless released a split album with another Ulf project, Nachtmahr. In it, he included the Tausend kalte Winter EP, Neunter November from the compilation album, and three new tracks, one of them being a cover of Burzum's Dunkelheit.

The project has been on hold while Ulf works on new releases with Nachtmahr and Noekk, and a rumored reunion with Empyrium.