(Preface) This new edition of Mozart's complete piano sonatas has involved a complete revision of the text owing to additional sources having since been made available, access to which was not possible in the preparation of earlier editions. Heading the critical analysis of each sonata the player will find the sources of reference consulted as well as their interrelationship. Since this urtext edition is intended to serve practical purposes, the editior has resisted the temptation to append a Critical Report such as is suitable for complete editions so as not to burden the volumne with excessive textual matter. Only the most important points at which the sources are at variance with one another are referred to either in the Preface of in appropriate footnotes. A detailed, type/written Critical Report is filed with the publishers and may be had on request. What proved to be a rather complicate task, as so often with Mozart, was the reproduction of the staccato signs, which appear in Mozart's handwriting either as dots or strokes (wedges). Since more various forms, we have refrained from distinguishing the two in order to preserve consistency, and have resorted to printing one single form of dot. Signs presumed to have been omitted inadvertently in the sources are placed in parentheses.