Finally, authors with strong political or philosophical points to make would no longer turn to the stage as their first hope of making a living. Prior to 1737, plays were "de rigueur" for authors who were not journalists. This had to do with the economics of booksellers. A bookseller would purchase a book from an author, whether that book was "Gulliver's Travels" or "Collected Sermons," and would calculate his chances of making money off of sales. He would pay the author according to the money he expected to make. (For example, Goldsmith's "The Vicar of Wakefield" was famously sold to pay a single rent installment, whereas John Gay had been paid 1,000 pounds for his "Poems on Various Occasions", which was more than seven years of salary for his government job). That would be the only money an author would see from the book, and therefore he or she would need to produce a new version, new book, or a serial publication of the next work to have hopes of more income. Prior to 1737, novelists had come from the ranks of satirists (Jonathan Swift) and journalists (Daniel Defoe), but these novels had in common wide changes of scenery, long plots, and often impossible things (such as talking horses)—all features that made the works unsuitable for the stage. The exception was Aphra Behn, who was a dramatist first and a novelist second. Her "Oroonoko" seems to have been written as a novel simply because there was no time for staging, as it was a political commentary on ongoing events, and she could not have another play on the boards at the time. Her "Love-Letters Between a Nobleman and His Sister", like "Gulliver's Travels" and "Moll Flanders", was inappropriate for the stage. However, after 1737, novels began to have dramatic structures involving only normal human beings, as the stage was closed off for serious authors.