Plains Indian men used to wear stories on their backs. Buffalo skins painted with the wearer's exploits in battle or the brave acts of his tribesmen were used to show status and displayed on ceremonial occasions. But beginning in the 1860s and 1870s, as the destruction of buffalo herds made hides scarce and Plains people were forced onto reservations, they began to use new materials to tell their stories. They drew with pencils and crayons on paper, often on the lined pages of ledgers obtained at trading posts or in raids.

The medium changed the message. Just as the tribes' own movements were now conscribed, artists were forced to find ways to render large movements onto a smaller surface, and developed a shorthand — four horseheads, for example, to show four stolen horses. And while hide art and early ledger art depicted battles, later drawings in ledgers, which could be shown more privately than buffalo skins, usually depicted domestic scenes: ceremonies, courtship, and rituals.

Two of a series of sketches said to have been drawn by Black Hawk, chief medicine man of the Sioux, depicting a dream. In one, a group of men and women watch a sun dance. In the other, a war horse and his rider are transformed into dream figures by "spirit energy," represented by the red and blue lines.
Courtesy of the Thaw Collection, Fenimore Art Museum, Cooperstown, N.Y.

More than 200 such ledgers exist, according to Ross Frank, an associate professor of ethnic studies at the University of California at San Diego. But they have been scattered among various collections or even taken apart by dealers eager to cash in on the market for American Indian art. Mr. Frank is working to preserve the books and keep them intact. His Plains Indian Ledger Art Project creates digital reproductions of entire ledger books that scholars and the public can browse on a Web site....