Intuition and a lack of imagination led to the complete undervaluation or oversight of Mozart's London Sketchbook from 1764 as a creative act. The author, a stylistically knowledgeable pianist, challenges the long-standing rigid view of Mozart's original short forms in his plea for the eight-year-old composer. He counters the imprecise work definitions of L. von Köchel with a new, verifiable classification of Mozart's drafts. As the editor of the urtext revision and the supplemented performance version (including fragments), he offers performers for the first time the opportunity to interpret these musical treasures meaningfully. New insights (cyclical work sequences, symphonic drafts, solo concerto movements, piano and organ pieces, dances, etc.), historical assessments, and psychological factors shed new light on Mozart's musical raw material.