Who wrote Song of Songs:

Song of Songs, also known as the Song of Solomon, was probably written by Solomon. Our only reason for believing this is the title suggests Solomon is the author and the book appears to be about Solomon (though some scholars claim Solomon and his bride is a metaphor for God and Israel).

We cannot be sure if Song of Songs was written by Solomon, or if an anonymous author wrote the book using Solomon as a main character. Because we have no solid reason to believe either theory, the matter remains open to debate.