About halfway through Moby-Dick (1851), Ishmael pauses to describe a beggar on the London docks. A one-legged man holds up a picture "representing the tragic scene in which he lost his leg" (p. 312). Not everyone believes this beggar's story, but, says Ishmael, "the time of his justification has now come" (p. 312). It is not that his story is true, but rather that "his three whales are as good whales as were ever published in Wapping" (p. 312). In one sense this self-published artist is a perfect amateur—a man whose works of art would never be printed in the modest commercial establishments found in the dockside neighborhood of Wapping. But he is also a professional—an artist with commercial aspirations, trying to live by selling his works.

As this scene suggests, it was not always easy to separate the amateur from the professional in the literary worlds of the first half of the nineteenth century. According to the...