<P> "Things Ain't What They Used to Be" is a 1942 jazz standard with music by Mercer Ellington and lyrics by Ted Persons . </P> <P> In 1941 there was a strike against the American Society of Composers, Authors and Publishers, of which Duke Ellington was a member . Because of the strike he could not air his songs on the radio . Instead, he used songs written by his son Mercer and pianist Billy Strayhorn . Strayhorn's compositions of this time include "Take the' A' Train", "Chelsea Bridge" and "Day Dream", and Mercer wrote "Things Ain't What They Used to Be", "Blue Serge" and "Moon Mist". </P>

Who wrote things ain't what they used to be