"You Can't Judge a Book by the Cover" is a 1962 song by rock and roll pioneer Bo Diddley. Written by Willie Dixon, the song was one of Diddley's last record chart hits. Unlike many of his well-known songs, "You Can't Judge a Book by the Cover" does not rely on the Bo Diddley beat. A variety of rock and other performers have recorded renditions of the song.
"You Can't Judge a Book by the Cover" is based on a sixteen-bar blues structure that "boasts a beat that's utterly compulsive and primordial, but closer to a way-speeded up walking rhythm than to the standard Diddley pattern".  Willie Dixon's lyrics use "a series of metaphors of all sorts of things you can't judge by their appearances before landing on the title phrase".
You can't judge an apple by looking at a treeYou can't judge honey by looking at the beeYou can't judge a daughter by looking at the motherYou can't judge a book by looking at the cover