 Others, such as "Oxford Reference", say 15.The collections were popular and commercial successes in the Christmas book market, and his publishers illustrated them with the leading illustrators of their time such as Gustav Doré and Richard Doyle.Far from being the blandly moralistic fare of the later Victorian period, "The Times" newspaper noted that his stories... "are of a very high order; light and brilliant narrative flow from his pen, and is fed by an invention as graceful as it is inexhaustible."