Opened in 1938. Ran 78 performances, to about March 1938. You Never Know is a musical with a book by Rowland Leigh, adapted from the original European play By Candlelight, by Siegfried Geyer and Karl Farkas, with music by Cole Porter and Robert Katscher, lyrics by Cole Porter, additional lyrics by Leigh and Edwin Gilbert, directed by Leigh, and songs by others. Wiki link