Dennis McKenna

Dennis McKenna is an American ethnopharmacologist and the younger brother of Terence McKenna, with whom he undertook the 1971 Amazonian expedition recounted in True Hallucinations and co-authored The Invisible Landscape (1975).

Where Terence became a verbal philosopher of the psychedelic, Dennis pursued a rigorous scientific career, earning a doctorate and conducting pharmacological research on ayahuasca, including participation in the landmark Hoasca Project that studied long-term ayahuasca users in Brazil.

He has been a board member of the Heffter Research Institute and a respected voice for evidence-based study of psychedelics. Dennis McKenna’s role in the mind-power lineage is the empirical complement to his brother’s visionary excess.

He represents the maturation of cyber-shamanism into legitimate science—investigating the actual neurochemistry of DMT, harmaline, and ayahuasca, and how traditional preparations achieve their effects. His careful work helps separate testable pharmacology from metaphysical speculation, and his presence lends scientific credibility to the entheogenic field.

He thus models the boundary this Atlas tries to mark: between the genuine, researchable phenomena of altered states and the unverifiable cosmological claims often attached to them.