Upright Instruction wherein the lovers of the clavier, and especially those desirous of learning, are shown a clear way not alone (1) to learn to play clearly in two voices but also, after further progress, (2) to deal correctly and well with three obbligato parts; furthermore, at the same time not alone to have good inventiones [ideas] but to develop the same well, and above all, to arrive at a singing style in playing and at the same time to acquire a strong foretaste to composition.

- Johann Sebastian Bach, preface to the Inventions and Sinfonias (2 and 3 part Inventions)