The corpus of twelve Latin theoretical treatises by the fifteenth-century Brabantine musician and lawyer Johannes Tinctoris (c.1435-1511) is acknowledged as one of the most significant and comprehensive sources for late medieval musical notation and compositional process, as well as a central focus for important recent research on musical aesthetics and reception at this crucial point in western European culture. Their content demonstrates not only an exceptional technical command of musical notation and theory, but also an intimate acquaintance with contemporary polyphonic practice, derived from a wide knowledge of the composers of his day and their music, both in northern Europe, where he began his career, and in Italy. This project will complete a new online edition of the whole corpus (also to be made available as a more permanent resource in DVD format), supplanting the existing edition (ed. Albert Seay, American Institute of Musicology, 1975-8) which has long been regarded by musicologists as highly unsatisfactory. The completed resource will greatly enlarge both the scope and accessibility of Tinctoris's work. Full English translations will be provided in addition to the Latin texts; in many cases these translations will be the first ever made, which will further enable the detailed significance of the treatises to be appreciated and explored by both scholarly and performance-based readers outside academia who are unable to handle the original Latin. Multiple layers of hyperlinked commentary material will also be provided, covering a wide range of technical and historical issues arising from both the texts themselves and the wider context of Tinctoris's life and musical environment in Renaissance Europe. Combining the highest levels of historical, textual and critical scholarship with innovative technological presentation, this open-access edition explores new methods of relating text-based materials to the numerous, often complex, music examples (both monophonic and polyphonic, mensural and non-mensural) that punctuate the treatises. An additional outcome will be the production of a new notation software package which will make available a wide spectrum of medieval and Renaissance musical notations for the first time to scholars, students, editors, publishers and performing musicians in a flexible and user-friendly application to a high professional level of historical and typographical accuracy. As the project progresses, the edition will have additional layers added which will use Tinctoris's primary texts as a pedagogical resource to enable users (e.g. undergraduate and postgraduate students, and early-stage scholars of pre-modern music repertories) to learn and practise the detail of late medieval notation through interactive engagement, independent virtual learning and self-testing.