My friend Oliver Sacks was at home, hoping to glimpse the color of heaven. It was 1964. He was in his kitchen in Topanga Canyon, preparing a cocktail. It wasn’t an ordinary cocktail, being part amphetamine (“for general arousal,” he told me), part marijuana (“for added delirium”), and part LSD (“for hallucinogenic intensity”), and his plan was to gulp, wait … and then command heaven to appear.

Oliver was not a believer. I’m sure he didn’t imagine a heaven with white clouds and angels darting about. White wasn’t his color. If heaven existed, he thought it would be bluish—not a pale blue, but “true indigo,” a rich, intense, deep blue that he had never seen. Nor had