Another Cahn and Van Heusen number. It sounds to me like a song from Sinatra's early years as a band singer and it's easy to picture 40s-era couples swaying to it on dance floor, but I believe it was written in the late fifties shortly before Frank recorded it. Very romantic, no?
That's the Reprise version from 1960, arranged by Nelson Riddle. But Frank recorded a slower version a couple of years earlier for Come Dance With Me (arranged by Billy May) that's also lovely.
*Update: For more background on the song from the lyricist himself, listen to Mark Steyn's Sammy Cahn podcast. It's an absolute must for Sinatra fans.