“Everything was under control. No, he mustn’t think about it, or indeed about anything, and especially not about heroin, because heroin was the only thing that stopped him scampering around in a hamster’s wheel of unanswerable questions. Heroin was the cavalry. Heroin was the missing chair leg, made with such precision that matched every splinter of the break. Heroin landed purring at the base of his skull, and wrapped itself darkly around his nervous system, like a black cat curling up on its favorite cushion. […]