Courtesy Treasury Friend Giovanni Rolla, who helpfully provides a translation of the ad copy:
"Sensational Match!
Cassius Clay wins!
You'll find it all in
'Superman Vs Cassius Clay!'
On sale at all newsstands"
I find it interesting that, in Italy at least, Muhammad Ali was still called Cassius Clay, years after he changed his name. Since this ad doesn't show the final cover, I wonder if they bothered to commission as nice a "Cassius Clay" logo as the Ali one seen on the original book.
Thanks so much Giovanni!