Carl Philipp Emanuel Bach
Carl Philipp Emanuel Bach (8 March 1714–14 December 1788) was a German musician and composer. He was the second of the five sons of Johann Sebastian Bach and Maria Barbara Bach. Besides composing and playing music he wrote a book called Essay on the True Art of Playing Keyboard Instruments. Many people have learned by playing music from it. C.P.E. Bach is often credited as composing the first truly classical piano sonata.