Schuberts piano sonatas written between 1818 and 1825 comprise four completed and five unfinished works. His breakthrough came with the Sonata in C major D 840, known as the Reliquie, the Sonata in A minor D 845, printed in 1826 entitled Premire Grande Sonate and as such the first sonata of Schubert that was published and the Sonata in D major D 850. H. G. Ngeli wrote enthusiastically to Czerny a short time later: I definitely count the piano composer Schubert among the good, even excellent ones.

With the publication of the Middle Sonatas, the three-volume Brenreiter Urtext edition of Schuberts piano sonatas is now complete. A detailed Foreword on the genesis and source situation as well as in-depth notes on piano playing in Schuberts time (including articulation, the use of pedal, ornamentation) with a special focus on Schuberts characteristic accent notation introduce the sonatas.