Check his wikipedia entry: "Asimov was one of the most prolific writers of all time, having written or edited more than 500 books ... His works have been published in all ten major categories of the Dewey Decimal System ... a master of hard science fiction ... also wrote mysteries and fantasy, as well as much non-fiction. Most of his popular science books..."

All that and amazing sideburns - in the literary world, second only to Henrik Ibsen