The Serenade in B flat major "Gran Partita" K 361, completed in 1781, is without doubt one of Mozart's most beautiful instrumental works..

Four hand music (not 4 hand piano): music written by two composers that both came from different musical backgrounds and culture
G.I. Gurdjieff - Twenty years later, in 1912, Gurdjieff returned to Europe, where he presented a new teaching: a non-religious path toward the inner evolution of man. Various generations of disciples gathered around his doctrine and his beliefs found strong echo in the work of Rene Daumal, P.D. Ouspensky, Alexander de Salzmann, Frank Lloyd Wright, Pierre Shaeffer, Peter Brook and T. De Hartmann himself.
T. De Hartmann - In 1912 he wrote the short essay "Anarchy in Music" which later appeared in the volume Der Blaue Reiter, by Kandisnky himself and Franz Marc. It proved to be one of the major manifestos of XXth century art. Keen on understanding the various bonds that connect different forms of artistic expression, De Hartmann was gifted in his research by an extremely free and unconventional spirit. Back in St. Petersburg, in 1916 he met Gurdjieff, who was to have a great influence in his life.

from the attached CD booklet