NIGHT AFTER NIGHT, RICHARD TOBIN sat in the attic of the 18th-century Ladd-Gilman House in Exeter, N.H., poring over piles of dusty papers that had collected there, uninspected, for more than two centuries. Nothing was going to uproot him—not even the 1 A.M. phone calls from Ellen, his wife. How could he leave? Tobin, 55, executive director of the newly created American Independence Museum at the historic house, was in the grip of what he calls the adventure of a lifetime. Talk about attic treasures! Here were letters from King Louis XVI, a Paul Revere engraving, the first Purple Heart—believed to have been sewn by Martha Washington, no less!

Then, on the strength of a note alluding to "other important papers," Tobin headed for a vault at Boston's Bank of New England. "I couldn't believe it at first—it was like winning the lottery twice," says Tobin. Inside were two drafts of the U.S. Constitution, one brought back from the 1787 Constitutional Convention by New Hampshire delegate Nicholas Gilman, the other by Massachusetts delegate Rufus King. (Both papers were placed in the bank around 1900.)

Only a handful of these documents are known to exist. "They are priceless," enthuses museum board member Bonnie Meroth, although one expert thinks the drafts could fetch better than a million apiece.

King's version is a four-page, near-final draft of the Constitution; the other is an earlier, seven-page committee draft annotated by Gil-man. The optimistic Tobin believes that Gilman's yet-to-be-deciphered marginalia could have "a significant impact on history."

But that's for the scholars to decide. Meroth and Tobin still have toys to unpack in the attic. "It's overwhelming," says Meroth. "We've been like kids in a candy store."