First came Johann Sebastian Bach's sonatas and partitas, then Nicolã Paganini's caprices. Now, with the op. 27 sonatas of Eugène Ysae, the key works in the repertoire for unaccompanied violin are available in urtext editions from Henle. Ysae peppered these challenging works with extraordinary difficulties, dedicating each of them to a virtuoso violinist of his day and tailoring it to suit his special capabilities. Thanks to newly discovered source material, we are able to present a definitive text that in many respects supersedes the previously available text from the first edition.