It would shed an instructive light upon authorship and the characters of famous men, if we could always know the relations between a writer and his booksellers.  Diderot’s point of view in considering the great modern enginery and processes of producing and selling books, was invariably, like his practice, that of a man of sound common sense and sterling integrity.  We have seen in the previous chapter something of the difficulties of the trade in those days.  The booksellers were a close guild of three hundred and sixty members, and the printers were limited to thirty-six.  Their privileges brought them little fortune.  They were of the lowest credit and repute, and most of them were hardly better than beggars.  It was said that not a dozen out of the three hundred and sixty could afford to have more than one coat for his back.  They were bound hand and foot by vexatious rules, and their market was gradually spoiled by a band of men whom they hated as interlopers, but whom the public had some reason to bless.  No bookseller nor printer could open an establishment outside of the quarter of the University, or on the north side of the bridges.  The restriction, which was as old as the introduction of printing into France, had its origin in the days when the visits of the royal inspectors to the presses and bookshops were constant and rigorous, and it saved the time of the officials to have all their business close to their hand.  Inasmuch, however, as people insisted on having books, and as they did not always choose to be at the pains of making a long journey to the region of the booksellers’ shops, hawkers sprang into existence.  Men bought books or got them on credit from the booksellers, and carried them in a bag over their shoulders to the houses of likely customers, just as a peddler now carries laces and calico, cheap silks and trumpory jewellery, round the country villages.  Even poor women filled their aprons with a few books, took them across the bridges, and knocked at people’s doors.  This would have been well enough in the eyes of the guild, if the hawkers had been content to buy from the legally patented booksellers.  But they began secretly to turn publishers in a small way on their own account.  Contraband was here, as always, the natural substitute for free trade.  They both issued pirated editions of their own, and they became the great purchasers and distributors of the pirated editions that came in vast bales from Switzerland, from Holland, from the Pope’s country of Avignon.  To their craft or courage the public owed its copies of works whose circulation was forbidden by the government.  The Persian Letters of Montesquieu was a prohibited book, but, for all that, there were a hundred editions of it before it had been published twenty years, and every schoolboy could find a copy on the quays for a dozen halfpence.  Bayle’s Thoughts on the Comet, Rousseau’s Emilius and Heloisa, Helvetius’s L’Esprit, and a thousand other forbidden pieces were in every library, both