Maria Estevez was 62 years old in 2006 when she participated in the second psilocybin study conducted by Roland Griffiths, a co-author of the Scientific American article on hallucinogens. The inspiration she derived from these experiences prompted her to write a yet-unpublished book about how it affected her life both during the study and afterward.
In this excerpt from One Kind of Knowing, quoted with permission, she recounts what occurred during the second and most intense of four experiences with the drug. The deeply spiritual quality of her perception of an inner light reveals how a shift in brain biochemistry can enable us to enter the realm of mystics and visionaries.