A collector of rare books ran into an acquaintance who told him he had just thrown away an old Bible that he found in a dusty, old box. He happened to mention that "Guten-somebody-or-other" had printed it.
"Not 'Gutenberg'?" gasped the collector.
"Yes, that was it!" said the acquaintance.
"You idiot!" yelled the collector. "You've thrown away one of the first books ever printed. A copy recently sold at auction for half a million dollars!"
"Oh, I don't think this book would have been worth anything close to that much," replied the man. "It was scribbled all over in the margins by some dude named Martin Luther."