I’ve been an admirer of the work of Michael Pollan since reading The Botany of Desire, in which he suggests that four plants (potatoes, tulips, apples and marijuana) have ensured their survival by generating a strong desire for them among humans. So when I noticed that he had taken on the topic of mind-altering drugs in How to Change Your Mind: the New Science of Psychedelics, my curiosity was piqued.