In its early stages, insomnia is almost an oasis in which those who have to think or suffer darkly take refuge. – Colette

[S]leep, and enough of it, is the prime necessity. Enough exercise, and good food and enough, are other necessities. But sleep—good sleep, and enough of it—this is a necessity without which you cannot have the exercise of use, nor the food. – Edward Everett Hale, “How to Get the Best of It,” c.1892

Judith slept far into the morning the sound, deep sleep of exhaustion; that sleep of the heavy-hearted from which, almost by an effort of will, the dreams are banished. – Amy Levy (1861–1889), Reuben Sachs: A Sketch, 1888

Impossible to spend sleepless nights and accomplish anything: if, in my youth, my parents had not financed my insomnias, I should surely have killed myself. – E. M. Cioran