Sleep, wrote Vladimir Nabokov in his 1967 autobiography, Speak, Memory, is a "nightly betrayal of reason, humanity, genius". Only dullards do it, apparently. "Sleep is the most moronic fraternity in the world," he declares. "It is a mental torture I find debasing." Nabokov's romanticization of the writer as a hyper-alert insomniac forging his creative path while the world is sleeping couldn't be more off-message today. It is, we now know, smart to sleep. Scientific research points to regular…