The isolation tank was developed in 1954 by John C. Lilly, a medical practitioner and neuropsychiatrist.[1][2][3] During his training in psychoanalysis at the US National Institute of Mental Health (NIMH), Lilly experimented with sensory deprivation. After 10 years of experimentation without taking any psychoactive substances, he tried floating in combination with a psychedelic agent, mostly LSD (at that time LSD was legal in the United States).