This poem is written by Willian Butler Yeats, he was an Irish poet. In December 1923 he awarded Nobel Price in Literature. His notable work includes when you are old , A dialogue of self and soul , Blood and the moon , etc.
This sweet, simple poem takes a much more traditional, rhyming form than most of Yeats's work. It depicts that Yeats stands over the cradle of infant and sees angles are also there. He kisses infant and sad because he knows he will miss the baby as it grows up.