A new interdisciplinary electronic resource, Ballad Operas Online (BOPO), hosted by the Oxford Digital Library (<http://www.odl.ox.ac.uk/balladoperas>), was officially launched internationally in July 2009. This project, designed and co-directed by myself and Michael Burden, has been funded by the John Fell OUP Research Fund and the British Academy.

Ballad Operas Online provides the first synoptic view of ballad operas and their music, cataloguing roughly two hundred operas – almost all produced between 1728 and 1736 – and their previously uncharted repertory of about 3,500 musical numbers. Through their popularity, ballad operas commercialized song on a scale and with a coordination between media that had never before been known. Ballad operas erased the boundaries between low- and high-style airs, widely distributed singers' images to market their productions, and, for the first time, broadly disseminated Handel's compositions in the public sphere. Ballad operas also contain delightful music, examples of which are available through the project's audio samples. The resource establishes the significance of this song market for audiences and composers, and aims to stimulate further research into the co-dependencies between the theatrical, musical and print industries of eighteenth-century London.

The resource's web pages explain this repertory's background and display examples of ballad opera notation, play books and frontispieces; singers' portraits and other iconography associated with ballad opera are also shown. The catalogue captures data on both individual operas and their music. Operas are catalogued by headword, under which details of the work are listed. Besides standard bibliographic information – title as printed, author, publisher – essential information concerning performances is supplied, including the first advertisement. To aid users, the resource displays the English Short Title Catalogue number of each opera's first edition, and whether the work is available for viewing at Eighteenth-Century Collections Online. Musical numbers are catalogued according to a uniform title system. To view data on music, users may either click on a link under the opera headword or call up air titles and their related data (composer, singer and first line, among other information). All fields are searchable, allowing users to verify, for instance, not only the number of ballad opera airs ascribed to Purcell, but also whether Purcell was mentioned in the first advertisement.

BOPO is designed to be the first stage of a larger, cross-institutional project that will recreate the soundscape of eighteenth-century London entertainment venues, and allow scholars from diverse disciplines to identify sources – textual, musical and iconographical – relevant to their research. Even in terms of ballad opera alone, there is a large amount of work yet to be done. The provenance of a ballad opera's music, the variations between its versions, the performance history of a production and the changes to its cast are among the most prominent types of data still lacking.

Electronic resources continue to be somewhat discipline-bound, yet intrinsic to their flexibility is the ease with which data may be exchanged between scholars working in different fields – a potential that is particularly important to exploit with regard to stage music. The site's audio samples are essential for showing non-music scholars the significance of musical evidence to their studies of eighteenth-century Britain. Readers of this journal are warmly invited to visit the website and send feedback on its utility.