Dr Mavromatis argues that this common, naturally occuring state may not only be distinct from wakefulness and sleep but unique in its nature and function, possibly carrying important evolutionary implications. He explores and analyzes the relationship between hypnagogia and other states, processes and experiences - such as sleepdreams, meditation, psi, schizophrenia, creativity, hypnosis, hallucinogenic drug-induced states, eidetic phenomena and epileptic states - and shows that, functioning in hypnagogia, we may gain knowledge of aspects of our mental nature which constitute fundamental underpinnings to all human thought. In addition functioning in hypnagogia is shown to play a significant part in mental and physical health.