This is an editorial ´tour de force´ of this seminal work. The inter-relationships between sources are especially challenging, and the resultant size of the critical commentary in this edition may at first appear daunting. However, the wealth of information it contains repays careful study; in particular, violinists who may have struggled with some of the awkward octave passages in the first movement will be gratified to learn that the source material reveals simpler, and fully authentic, alternatives. Howat also examines in illuminating detail the relationships between bowing and phrasing, the appropriate placing of dynamic markings (sometimes inconsistent across the sources) and of course the ever-present questions of tempo and metronome indications.