{"product_id":"9781580442992","title":"Guy of Saint-Denis, Tractatus de tonis","description":"The Tractatus de tonis of Guy of Saint-Denis (written ca. 1300-10) differs from other treatises on plainchant in the depth of its analysis of the various tones into which chant was traditionally classified. Guy's treatise presents itself as a synthetic overview of both the theory and practice of plainchant in a way that combines the practical reflection of Guido of Arezzo with ideas of more Aristoteleian inspired theorists such as Johannes de Grocheio and Peter of Auvergne.","brand":"Medieval Institute Publications","offers":[{"title":"Default Title","offer_id":47055369994480,"sku":"9781580442992","price":89.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0737\/7593\/9824\/files\/9781580442992_p0.jpg?v=1763801949","url":"https:\/\/shop-qa.barnesandnoble.com\/products\/9781580442992","provider":"Barnes \u0026 Noble (DEV)","version":"1.0","type":"link"}