This is like having a time machine," says Mark Mitchell of Vienna, paging through a neatly bound collection of Harper's Weekly newspapers from the Civil War period. Mitchell purchased his first antique newspaper for a sawbuck in 1975; within a few years, he had traded a job in the State Department's passport office for a full-time career as a rare newspaper collector and dealer. Now he has about 10,000 newspapers that he values at "upwards of $6 million" stored in a secure warehouse.

There is, for example, the framed copy of the March 10, 1862, New York Times describing the battle between the Monitor and the Merrimack. It's immaculate -- and worth about $5,000, compared with the 2 cents it originally cost. "But condition is nowhere near as critical for newspapers as it is for stamps or coins," Mitchell says. "Age, rarity and historical significance are far more important in determining value."

He trots out a February 23, 1719, copy of the Boston News-Letter describing "a great, bloody, Errol Flynn type sword fight" that resulted in the death of pirate Edward Teach, better known as Blackbeard. "It's the only known issue of this paper, which makes it worth the asking price of $250,000," Mitchell says.

Sometimes it's not so easy to find the significant stories. Nestled among a dozen or so humdrum items in a December 18, 1903, St. Louis Globe-Democrat is one modestly captioned: "Airship Flies In The Face Of Wind."

"That's the way they reported the Wright brothers' first airplane flight!" says Mitchell, shaking his head. "An event that would forever change the way we live."