Not long ago, Steven Lubar, lead curator for technology at the Smithsonian Institution’s National Museum of American History, decided to add a robot dog to the museum’s consumer-electronics collection. Executives at Sony were happy to send him an AIBO fresh off the assembly line, but Lubar insisted on one that had been used. So Sony found him a woman in Washington state who wrote poems about her mechanical pooch and choreographed routines for it. When they reached her, Lubar and his colleagues were able to persuade her to donate her cherished pup.

This episode demonstrates the museum’s new attitude toward artifact collecting—an approach elucidated in a new book, Legacies: Collecting America’s History at the Smithsonian, by Lubar, 46, and NMAH assistant curator Kathleen Kendrick, 29. Although for a century and a half the museum has collected objects of obvious historical significance (such as the original Star-Spangled Banner), items owned or used by famous people (such as Abraham Lincoln’s top hat), and artifacts of important advances in science and technology (the locomotive John Bull, for instance), curators in recent years have tried to collect items that explain how ordinary Americans have lived their lives. “It’s a change in the way museums think,” Lubar says. “Is it about showing the history of furniture? Or about how people lived in their homes?” By collecting both objects and the stories behind them, Lubar says, “you’re adding another layer.”

Legacies—which was put together to accompany a permanent, introductory exhibition to the museum that has not been mounted yet—represents the first book-length treatment of the museum’s collections in two decades. During that period, the makeup of the museum’s collection has changed dramatically. Computers and other electronic items have multiplied. Curators have eagerly sought out pieces that represent ethnic, racial, and religious minority groups, and have also been on the lookout for crowd-pleasing pop-culture artifacts, ranging from Barbie dolls to Spock’s ears. (Such items are sometimes expensive, because the museum often has to compete with Hard Rock Cafes and private collectors in the marketplace.)

To put together the book—which spotlights a cross-section of items from the collection—Lubar and Kendrick dug through the museum’s voluminous acquisition files, which include memos by curators and letters from donors explaining their motivations. That method enabled the authors to spotlight not only the museum’s possessions but also the backstories that explain their historical significance and why they were collected. One of Kendrick’s favorite items, for instance, is a Jewish Torah scroll made in 1914 by an immigrant who decorated it with an American flag and patriotic quotations—to Kendrick, an embodiment of American assimilation. The authors also like a pair of worn bell-bottom jeans sent to the museum by the girl who owned them. “These jeans aren’t art, but they’re a sample of costume in America,” she wrote. “Best of all, they’re authentic.”

Most items donated over the transom are rejected; space at the museum and its two satellite storage locations, in Maryland and Virginia, is limited. Because of complicated deaccession rules, getting rid of old items often isn’t easy. And some pieces—such as the display that includes locks of hair from every president from George Washington to Franklin Pierce—can’t really be given away. “That encapsulates how what is considered important has changed,” Lubar says. “No one today is collecting hair locks of the presidents.” —Louis Jacobson