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When I began my graduate studies in 1969, it was politically correct in scientific circles to refer to these substances only as psychotomimetics, a negative term suggesting that they fostered a mental state resembling psychosis ( Hoffer, 1967). I was delighted when the editors invited me to write a review on “psychedelics,” perhaps a watershed moment, representing a shift in opinion that has been developing for more than 3 decades with respect to research and understanding of psychedelics. Recently, blood oxygen level–dependent functional magnetic resonance imaging and magnetoencephalography have been employed for in vivo brain imaging in humans after administration of a psychedelic, and results indicate that intravenously administered psilocybin and LSD produce decreases in oscillatory power in areas of the brain’s default mode network. Two small pilot studies of psilocybin-assisted psychotherapy also have shown positive benefit in treating both alcohol and nicotine addiction. Recent and exciting developments in the field have occurred in clinical research, where several double-blind placebo-controlled phase 2 studies of psilocybin-assisted psychotherapy in patients with cancer-related psychosocial distress have demonstrated unprecedented positive relief of anxiety and depression. Several useful rodent models have been developed over the years to help unravel the neurochemical correlates of serotonin 5-hydroxytryptamine 2A receptor activation in the brain, and a variety of imaging techniques have been employed to identify key brain areas that are directly affected by psychedelics. Today there is a consensus that psychedelics are agonists or partial agonists at brain serotonin 5-hydroxytryptamine 2A receptors, with particular importance on those expressed on apical dendrites of neocortical pyramidal cells in layer V. After the virtually contemporaneous discovery of (5 R,8 R)-(+)-lysergic acid- N,N-diethylamide (LSD)-25 and the identification of serotonin in the brain, early research focused intensively on the possibility that LSD and other psychedelics had a serotonergic basis for their action. Their origin predates written history, and they were employed by early cultures in many sociocultural and ritual contexts. They are generally considered physiologically safe and do not lead to dependence or addiction. From this need, Moellering (1980a) has developed the concepts of real and virtual maps.Psychedelics (serotonergic hallucinogens) are powerful psychoactive substances that alter perception and mood and affect numerous cognitive processes. As this work in cartography has accelerated, so has the need for specifying an expanded model for what constitutes a map. Morrison clearly recognized this need as did Riffe (1970). These prodigious efforts, as well as many others, have resulted in a large number of new cartographic products and systems which go far beyond the conventional definition of a map. One can see development taking place in numerical processing (see for example Aangeenbrug (1980)), analytical cartography (Tobler, 1979), cartographic data base development (Nyerges, 1980), geographic information systems (Tomlinson et al., 1976), and cartographic systems design and operation (Aangeenbrug, 1980). Many of the trends recognized by Morrison also apply to general cartography as well. The second is a perception of the field of cartography as an independent scientific discipline. The first aspect which is important here is the expansion of the definition of the concept of a map which includes the newer cartographic products and a recognition of the new strategies for mapping methodology. This trend was recognized some time ago by Morrison (Morrison, 1974) in a perceptive article in which he discussed the changing philosophical and technical aspects of thematic cartography. In the last decade, numerical and analytical approaches to cartography have been growing at a rapid rate (Robinson et al., 1977).