It is a seven-hour album on a DVD-video that was partly inspired by Rich's sleep concert series of the early 1980s and mid 1990s.

For this purpose it is suggested that the volume be kept down to the threshold of perceptibility, ideally with speakers surrounding the listener's bed.

For a brief period at the beginning of the album there is a slightly more active texture while the listener adjusts the volume and settles down to sleep.

As the music progresses it slowly drifts through a variety of electronic drones as well as acoustic source material and nature recordings.

Instead, Robert Rich himself released a follow-up on Blu-ray in 2014, Perpetual, including an 8-hour piece of the same name plus a re-issue of Somnium in full length.