Medicine is my lawful wife, and literature is my mistress. When I get fed up with one, I spend the night with the other. Though it is irregular, it is less boring this way, and besides, neither of them loses anything through my infidelity.

Night is irregular. What is not done in the daytime becomes possible at night: murder and sex and thought. Simple men are driven to early beds by tomorrow's daytime demands and by fear of the dark, and never dream of the irregular world outside. And all the while, a viscount and a spaceport baggage boy might be passing the night rolling bok ball in the city park. That's more than unusual -- that is irregular.