though we've heard this song countless time , very few of us know much about its history. the melody and lyrics were written by two sister--Mildred J.Hill and Patty Smith Hill. Patty was a schoolteacher at Columbia University Teachers' college. Mildred was also an educator who later ob became a composer , organist and pianist. The melody was composed by Mildred and the lyrics were written by Patty , but it was originally for a classroom greeting song titled 'Good Morning to All', which was part of the book 'Song Stories for the Kindergarten' published in 1893. From then the lyrics were changed firstly to Good Morning to you and then finally Happy Birthday to You. it is still unclear who changed the lyrics that turned it into a birthday song, but it was first published in 1924 in a book edited by Robert H. Coleman Now it is a global smash