Writing a book is a horrible, exhausting struggle, like a long bout of some painful illness. One would never undertake such a thing if one were not driven on by some demon whom one can neither resist nor understand. – George Orwell, “Why I Write,” 1947 (Thanks, Jennifer)

It is indeed certain, that whoever attempts any common topick, will find unexpected coincidences of his thoughts with those of other writers; nor can the nicest judgment always distinguish accidental similitude from artful imitation. – Samuel Johnson, 1751