I was always fascinated by dreams and dreaming. In my youth, I had vivid dreams; later in my life, I became an insomniac and had sleep apnea. So my doctor sent me to an overnight sleep study where they hooked me up with all sorts of electrodes to measure my sleep and wake cycle and the qualities of my sleep. I was uncomfortable and lay there for over five hours, apparently awake. Finally, at dawn, the assistant said I could unhook myself and go home. Following days they sent me a report that I was sleeping for four hours and my apnea was quite severe. I was astonished; I thought they would have to repeat the study due to a lack of data. My first Yoga teacher said that when we dream, we are out of the gross (physical) body and enter a state via the subtle (invisible) body. He said he often spoke to his long-deceased Guru.