The Strachwitz Frontera Collection is the largest repository of commercially produced Mexican and Mexican American vernacular recordings in existence. More than 40,000 recordings, all produced during the first half of the 20th century, have been digitized and are available to researchers and the general public online. Although border music is the focus of the collection, it also includes notable recordings of other Latin forms, including salsa, mambo, sones, and rancheras. Agustin Gurza explores the Frontera Collection, discussing genre, themes, and some of the thousands of performers whose recordings are archived. He considers the cultural significance of the recordings, notably what the lyrics reveal about relationships between not only Anglos and Mexicans but also Mexican nationals and other immigrant and ethnic groups. Jonathan Clark focuses on recordings by mariachi ensembles. Topical lists of recordings and a guide to the collection with suggestions for searching the online files complete the volume.