In his new book How To Change Your Mind: The new science of psychedelics, Michael Pollan sets out the twentieth-century history of the use of “psychedelic” substances with clarity, insight and humour. He does his fieldwork – with appropriate trepidation. He goes mushroom hunting. He consumes four different psychedelic tryptamines under suitably controlled conditions – LSD, psilocybin, ayahuasca (active ingredient N, N-dimethyltryptamine, sc DMT), and, with shattering results, 5-MeO-DMT, the smoked venom of the Sonoran Desert toad Incilius alvarius – and tells us, as well as he can, what happens. He ends with two chapters laying out the latest neuroscientific speculations and describing the extraordinarily fruitful renaissance of the use of psychedelics in psychotherapy in the 1990s. Read the whole review here.