In 1988 Keith Feinstein bought a Star Wars arcade game for his college dorm room. Besides keeping him in beer and pizza money for the next four years, it also launched him on a personal journey that has lasted into the present: he now owns more than 900 vintage video arcade games, which he exhibits in a traveling show known as Videotopia. "People cry," says Feinstein, who is now 34, and who remembers a childhood complete with the earliest Pong console and an Atari 2600 he loved. "They can walk into an exhibit with hundreds of machines, and in all that incredible cacophony, they run right to their game. These games were a part of our lives. They were our first interactive media." Some of Feinstein's lovingly preserved devices are probably the last working models on the planet-the only machines where the 20-year-old software behind these games can come alive on the hardware it was meant for.

Just about the time Feinstein bought his first arcade game, Abby Smith was completing a PhD in medieval Russian history at Harvard University. She was troubled, though, that only a handful of writings from before the 14th century-mostly liturgical documents-had survived the tumult of Russian history. How much had been irretrievably lost? How much of her own time was going to be lost to the future? Something about those questions struck Smith as far more interesting than the work she was doing, so she threw over Russian history to specialize instead in library science. For the past two decades, Smith has helped the U.S. Library of Congress in its task of preserving history. At first she occupied herself with such tasks as saving Lincoln's original Gettysburg address from deterioration, but as our culture has grown more digital, Smith has in turn become ever more focused on solving the problem of preserving digital artifacts. She is currently director of programs at the Council on Library and Information Resources, a Washington, DC, nonprofit organization that's helping the Library of Congress draft a proposal asking legislators to fund research on a long-term solution. "The layman's view is that digital information is more secure, when in fact it's far more ephemeral," she says. "We know how to keep paper intact for hundreds of years. But digital information is all in code. Without access to that code, it's lost."

Smith and Feinstein are working opposite ends of the same problem: how to preserve digital things-data, software and the electronics needed to read them-as they age. Paper documents last for hundreds of years, but more and more of what matters to us is digitally produced, and we can't guarantee that any of it will be usable 100, or 10, or even five years from now. Feinstein's contribution toward staving off digital obsolescence is to scour flea markets for old circuit boards that might have the chips he needs to repair old games; he is obsessed with keeping every game in his collection working. Smith's approach is to develop a plan for preserving culture itself; she is obsessed with guaranteeing, for example, that 300 years from now, people will be able to read files that locate nuclear-waste sites. Both are faced with the knowledge that current methods for preserving digital things work poorly, even in the short term.

Just how bad is the problem? Examples of digital things lost forever abound, some personal in scale, some global. Software patents that can be infringed freely because the original software no longer works, preventing the patent holders from proving prior art. Land use and natural-resource inventories for the State of New York compiled in the late 1960s that can't be accessed because the customized software needed to open the files no longer exists. NASA satellite data from the 1970s that might have helped us understand global warming, were they not unreadable today.