Like many of his fellow Baroque composers, Bach was an astonishingly resourceful and skilful "second user" of his own music. Some of the harpsichord concertos, for example, probably have a Weimar prehistory as chamber concertos for various solo instruments. Here, Michael Form sets out with great detective instinct to reconstruct these presumed original versions. We thus experience nothing less than the rediscovery of an almost forgotten Baroque genre: the so-called Concerto da Camera for several solo instruments without orchestral accompaniment.