The knowledge of the early keyboard works of Johann Sebastian Bach has come to a considerable extent from this manuscript which is archived in the Staatsbibliothek in Berlin.
It contains 12 pieces by the young Bach, written in the early years of the 18th century, as well as music by some of the most famous German composers of the time like Georg Böhm, Nicolaus Bruhns, Dietrich Buxtehude, Johann Adam Reinken and Friedrich Wilhelm Zachow.
In addition there are transcriptions of orchestral music by, for example, the 17th century French master Jean-Baptiste Lully.
Therefore, the manuscript gives insight into the kind of music that he was interested in and influenced his composing.
Some of the pieces in the manuscript are not known from any other source, such as the short 'Gigue belle' by Werner Fabricius.