Reddit reviews The Pursuit of Oblivion: A Social History of Drugs

https://www.amazon.co.uk/gp/product/1842125524/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

try showing them this TED talk graham hancock has some pretty far out ideas, but the idea that drugs helped us understand the world way was before the societal norms that ban them is a pretty solid one i think. there's also this book which really puts humanities relationship with drugs in perspective. if nothing else, it might show them that drugs are not the preserve of indolent hippies but are inimately bound to the human experience. hope it helps anyway, and enjoy your shrooms!!