Mr. Porter wrote "What Is This Thing Called Love?" in 1929. Twenty-six years later Sinatra and Riddle made the above masterpiece, early in their partnership. I have to quote Mark Steyn's piece on the song, which he featured as #10 on his Sinatra 100 list:
By contrast with the music, the words are simple, at least by Porter's standards - no flashy rhymes, no wordplay, no allusions or imagery. On the page they can look rather trite - one wonderful day you threw my heart away:Powerful and beautiful. Read all of Mark's essay.
That's why I ask the Lord in Heaven above
What Is This Thing Called Love?
But Porter knew what he was doing: The words are simple, but the music tells you that the answer to the question is complex and profound and ultimately unknowable. Its the combination of unaffected directness in the lyric and great depth in the music that gives the song its power.