According to his first biographer Johann Nikolaus Forkel, Bach possessed an extraordinary ability to combine organ stops in a wholly unusual manner, astonishing the organists and organ builders of his time. However, very few accounts survive of how he actually made these timbral choices. A valuable source of information is the Harmonische Seelenlust by Georg Friedrich Kauffmann (1733-36), a large collection of chorale preludes that displays striking points of contact with the third part of the Clavier-ubung (1739) - to the point of appearing almost as a model for it - and includes registrations so original and bold as to recall the style described by Forkel. Having already distinguished himself with the award-winning Bach Mirrored (Preis der Deutschen Schallplattenkritik), organist Maurizio Croci draws on the timbral resources of the historic Treutmann organ at Grauhof (1737) to offer us a fresh reading of Bach's masterpiece which, taking inspiration from Kauffmann's registrations, places registration at the centre of expressive interpretation and proposes a renewed listening perspective.