Toccata and Fugue in D minor, BWV 565 - 1. Toccata

Johann Sebastian Bach (31 March [O.S. 21 March] 1685 – 28 July 1750) was a German composer and musician of theBaroque period. He enriched established German styles through his skill in counterpoint, harmonic and motivicorganisation, and the adaptation of rhythms, forms, and textures from abroad, particularly from Italy and France. Bach's compositions include the Brandenburg concertos, the Mass in B minor, The Well-Tempered Clavier, two Passions, keyboard works, and more than 300 cantatas, of which nearly 100 cantatas have been lost to posterity. His music is revered for its intellectual depth, technical command, and artistic beauty. [source from Wikipedia]

This is the most famous organ work of Bach. The musical animation Fantasia produced by The Walt Disney Company in 1940 also selected this music as one of the sections. The music starts with an Adagio in the beginning and then enters the brilliant Fugue.