This is one of the great classic jazz pieces. Charlie Mingus was a bass player and composer. He wrote this song as a tribute to Lester Young. This was the original version most people heard from the album Ah Um. It was produced in a studio in 1959.
It has been done by many people since. One notable version is by Joni Mitchell with lyrics she composed. She worked with Mingus not long before his death and produced an album called Mingus.