Any performer of Mozart's piano concertos must have wondered how those sparsely notated sections would have been realized at the time. No one is better placed to provide an answer than the composer's own pupil Johann Nepomuk Hummel. The present edition includes a separate piano part, in addition to the same part contained within the full score, for two reasons. The first is that of convenience: the greater compactness and smaller number of page turns will be of benefit to the pianist learning an...