12/5/58 Morning I rotated again, and again found the hole. Still with a note of caution, I approached the hole, and this time reached through with bo… - Robert Monroe

We had no idea that sounds existed beyond the range of human hearing until we developed instruments to detect, measure, and create them. Until comparatively recently, those who claimed they could hear what others could not were considered insane or persecuted as witches and sorcerers. We were able to perceive the electromagnetic spectrum only in terms of heat and light until the last century. We are still unaware of the capacity of the human brain, an electrochemical organism, in terms of transmission and reception of electromagnetic radiation. With this gap unbridged, it is easy to understand why modern science has not begun to consider the ability of the human mind to penetrate an area where no serious theory has been promulgated.

Most of all, who quietly insisted that I return to the physical when I drifted in that seemingly eternal bliss? I don't know whether to be grateful or sad for that particular help.

The first step in making some kind of sense out of this mass of raw data was to set up standards for measurement and analysis. After several attempts, it became apparent that only a few of the typical yardsticks could be applied. Therefore, assumptions or premises were made to permit identification in the sorting process, and the conclusions brought forth are only as valid as the premises on which they are based.