Henrik Nordvargr Björkk
Sleep Therapy

Talking about this "work" puts me in absolute difficulty, and I don't see how it could be otherwise. Henrik Nordvargr Björkk, one of the global gurus in the world of dark ambient, thanks to works such as the icy "Awaken," deadlier and more black metal than all black metal; a name that commands respect among those in the circle. Typically, he does dark ambient. Then he made this "Sleep Therapy." And "Sleep Therapy" is not dark ambient. To tell the truth, it's not even music. If we really want to be precise, it's not even an album, but a serious experiment. Not for entertainment purposes, in short.
First, a bit of theory alla cazz de can: the dominant frequency in the EEG pattern determines the brain's current state. Different waves have different frequency ranges (from the Delta peak at 3.9 hertz to the 30 of the Beta - which are recorded in a state of consciousness) and consequently define different brain states. For example, if the amplitude of the Theta frequencies is the highest (hence dominant), the brain is said to be in a Theta state. The brain can also be stimulated from the outside, bombarding it with frequencies different from those dominating, taking it from one state to another. If we were, I don't know, in Beta state (as illustrated before, hence conscious) and received a prolonged stimulus of Delta waves (which characterize the deep sleep phase), we would be brought to be in a Delta state. Fascinating, huh? I know it doesn't make sense; I did my best.
The "Sleep Therapy" experiment is based precisely on this: eight discs, one for each day of the week (plus one final at the end of the "treatment"), to be listened to before falling asleep. All tracks are composed of lower-frequency waves, namely - indeed - Delta, characteristic of deep sleep, and Theta, characteristic of the REM phase (that phase where we might rather want to listen to "New Adventures In Hi-Fi"). What is heard during listening, however, are only incessant signals at very low (but audible) frequency. On the other hand, if it were composed only of those two waves, we wouldn't hear anything. Considering that the highest frequency reached by them is around 8 hertz, and humans cannot hear anything below the threshold of 20Hz. In the end, listening to these tracks (using strictly high-quality headphones, not 5 euro earbuds - even at a very low volume, it has an effect -), our encephalon will be stimulated, and the dominant wave of our brain will change, and with it our brain state, thus leading to... Sleep. What else?
A few months ago, after discovering this project, curiosity rose, and I subjected myself to the experiment. I've never been a fan of these things, but it was certainly the most particular experience of my life. Also because, incredibly enough, it even worked. It was my cure for insomnia for about 3 weeks, then I messed up my circadian rhythm again and didn't try anymore. Apart from that, the whole thing is extremely interesting and probably should be tried at least once. 
(The only downside is that it is practically impossible to find. Original copies have sky-high prices, and to download, well... I'll just tell you that I had to browse through Google results for about three hours before finding anything concrete. Anyway, this writing came out horribly.)