Johann Sebastian Bach was a German composer and musician of the Baroque period. He is known for his mastery of counterpoint, harmony, and musical forms. Bach's compositions include organ works, choral music, orchestral suites, and solo instrumental music. His music is characterized by its intricate polyphony and profound spirituality. Bach's most famous works include his 'Brandenburg Concertos,' his 'Mass in B minor,' and his 'Well-Tempered Clavier.'