The fifth volume of Masaaki Suzuki’s series of Bach’s works for organ features one of the most important surviving instruments from Bach’s time, made by the German organ builder Christoph Treutmann the Elder. Widely known for its extraordinary tonal quality, the instrument was built between 1734 and 1737. A recent general restoration preserved all essential structural elements or renewed them while remaining faithful to the originals, making this an ideal instrument for Bach interpreters who wish to come close to the sound world of the Leipzig Thomaskantor. Suzuki now takes up the Orgel-Büchlein (literally, “little organ book”), a collection of 45 short chorale preludes on melodies from the Lutheran hymn book, a project that came into being in connection with Bach’s appointment as organist and chamber musician at the Duke’s court in Weimar in 1708. Presenting chorales for different periods of the church year, this collection serves as a general guide to text-based composition focusing on wordsound relationships and content-specific musical expression. Three Preludes and Fugues complete the second volume dedicated to the Orgel-Büchlein, illustrating the principle of variety and structure historically practised by concert organists in order to demonstrate the tone colours and expressive possibilities of their instrument.