The Inventions and Sinfonias, BWV 772–801, also known as the Two- and Three-Part Inventions, are a collection of thirty short keyboard compositions by Johann Sebastian Bach (1685–1750): 15 inventions, which are two-part contrapuntal pieces, and 15 sinfonias, which are three-part contrapuntal pieces. They were originally written as musical exercises for his students. They were originally written as "Praeambula" and "Fantasiae" in the Klavierbüchlein für Wilhelm Friedemann Bach, a Clavier-booklet for his eldest son, and later rewritten as musical exercises for his students.
The inventions were composed in Köthen; the sinfonias, on the other hand, were probably not finished until the beginning of the Leipzig period. The autograph fair copy is dated 1723.
The four duetti BWV 802–805 were included at a fairly late stage in 1739 in the engraved plates for Clavier-Übung III. The use of the term duetto itself is closest to that given in the first volume of the Critica Musica (1722) of Johann Mattheson: a piece for two voices involving more than just "imitation at the unison and the octave". The purpose of the Bach's Duets has remained a source of debate.
The recording was done using Bruel & Kjaer microphones, two pairs, and Prism Sound preamps and converters in the Saletta Acustica 'Eric James', Italy.