In following Defoe's career, we are constantly reminded that he was a man of business, and practised the profession of letters with a shrewd eye to the main chance. He scoffed at the idea of practising it with any other object, though he had aspirations after immortal fame as much as any of his more decorous contemporaries. Like Thomas Fuller, he frankly avowed that he wrote "for some honest profit to himself." Did any man, he asked, do anything without some regard to his own advantage? Whenever he hit upon a profitable vein, he worked it to exhaustion, putting the ore into various shapes to attract different purchasers. _Robinson Crusoe_ made a sensation; he immediately followed up the original story with a Second Part, and the Second Part with a volume of _Serious Reflections_. He had discovered the keenness of the public appetite for stories of the supernatural, in 1706, by means of his _True Relation of the Apparition of one Mrs. Veal_.[4] When, in 1720, he undertook to write the life of the popular fortune-teller, Duncan Campbell--a puff which illustrates almost better than anything else Defoe's extraordinary ingenuity in putting a respectable face upon the most disreputable materials--he had another proof of the avidity with which people run to hear marvels. He followed up this clue with _A System of Magic, or a History of the Black Art_; _The Secrets of the Invisible World disclosed, or a Universal History of Apparitions_; and a humorous _History of the Devil_, in which last work he subjected _Paradise Lost_, to which Addison had drawn attention by his papers in the _Spectator_, to very sharp criticism. In his books and pamphlets on the Behaviour of Servants, and his works of more formal instruction, the _Family Instructor_, the _Plan of English Commerce_, the _Complete English Tradesman_, the _Complete English Gentleman_ (his last work, left unfinished and unpublished), he wrote with a similar regard to what was for the moment in demand. [Footnote 4: Mr. Lee has disposed conclusively of the myth that this tale was written to promote the sale of a dull book by one Drelincourt on the _Fear of Death_, which Mrs. Veal's ghost earnestly recommended her friend to read. It was first published separately as a pamphlet without any reference to Drelincourt. It was not printed with Drelincourt's _Fear of Death_ till the fourth edition of that work, which was already popular. Further, the sale of Drelincourt does not appear to have been increased by the addition of Defoe's pamphlet to the book, and of Mrs. Veal's recommendation to the pamphlet.]