The "Night Before Christmas" is a famous Christmas poem that was first published anonymously in 1823, under the title "A Visit from St. Nicholas." It is believed to have been written by Clement Clark Moore, a professor of Hebrew and Oriental literature at Columbia University in New York. The poem was an instant hit, and it quickly became a popular Christmas tradition to read it on Christmas Eve. Over the years, it has been adapted into various forms, including movies and songs, but the original poem still remains a beloved classic.