Exhibition at the atrium of the Public Library and Regional Archive of Angra do Heroísmo, from October 1-15 2012, commemorating the World Music Day. This exhibition is made of a collection of music treatises by Portuguese authors, from seventeenth-century António Fernandes “Arte de Música” to twentieth-century work by Luís de Freitas Branco. Most of these works were part of the private library of Portuguese Angra do Heroísmo-born composer Tomás Borba.