Reading was at a low ebb in the Stone Age,"" begins the irrepressible author of It All Started With Fill-in-the-Blank, but there were a few compensations for librarians--simplified record-keeping, for example. Things picked up a bit with the Sumerians and Babylonians, who ""learned to place needed works where they could be found only by a qualified librarian,"" and the Romans, who advanced the cause of the card file no end by inventing the Latin alphabet. By the end of the Middle Ages Johannes GÃ„nsefleisch, vulgarly known as Gutenberg, had dreamed up movable type, and ""literacy was becoming as widespread as syphilis and gonorrhea,"" thereby increasing the demand for librarians. Still, the profession didn't really come into its own until the great watershed of the Dewey Decimal System, which ""requires only a knowledge of all recorded knowledge and the ability to divide by ten."" What of the future? Well, there are no limits to the possibilities of microfilm, and perhaps we can look forward to an era when librarians will be fed a bit of mushroom, Alice-in-Wonderland style, at the start of the working day and the opposite kind of mushroom at quitting time. . . . Mostly for Armour fans: about three and a half very funny ideas to every ten clinkers, but that's still batting .350.