I am learning my business. Literature nowadays is a trade. Putting aside men of genius, who may succeed by mere cosmic force, your successful man of letters is your skilful tradesman. He thinks first and foremost of the markets; when one kind of goods begins to go off slackly, he is ready with something new and appetising. He knows perfectly all the possible sources of income. Whatever he has to sell he'll get payment for it from all sorts of various quarters; none of your unpractical selling for a lump sum to a middleman who will make six distinct profits.

Vol. I, Ch. 1 : A Man of His Day, p. 8 - New Grub Street : A Novel (1891)