Vintage sheet music. $1 to $35. Lorna Lethbridge Priest Antiques, 4233 Howard Ave., Kensington. 942-8746.

In the days before electronic acquisitiveness gripped the family's attention, before video games and quadraphonic sound machines took over the living room, the focal point of parlor life was the piano. Then, a good advertising technique was to print up some piano sheet music and put your company's logo on it, as Bromo Seltzer did in the 1890s. Some newspapers even carried pull-out-save-sheet music. The history of American sheet music is the history of the times, mirroring in the lyrics and the cover illustrations the state of politics, the fads, the wars, the stars of stage, and eventually, screen. "They always reflected sociological and historical changes," says Lorna Lethbridge Priest, a Kensington antique dealer, who, with her husband Daniel, has accumulated an estimated 5,000 pieces of sheet music, some of it dating back to the Civil War. Priest says that vintage sheet music has its own clique of collectors who look for music on specific subjects or with certain names. She also thinks that the attractiveness of the cover illustrations makes many pieces frameable. In trying to classify their collection, Priest has come up with more than a dozen categories -- people's names, war songs, Indian songs, songs about islands, Irish songs, music from movies (the most popular), and, she says, "we've got so many songs for the lovelorn."