The book of Koheleth is not a pseudepigraph, seeking to masquerade as the authentic work of Solomon. If that were the author’s intention, he would have adopted the name “Solomon” outright, instead of inventing the enigmatic name “Koheleth”, which suggests the identity only by indirection. It should be remembered, too, that he does not call himself “son of David”; this phrase occurs only in the opening verse, which is the title of the book and emanates from an editor. That this identification played a large part in gaining admission for the book into the canon is one of the fortunate accidents of literary history, but does not gainsay the fact that it does not go back to the author.
Robert Gordis, Koheleth – The Man and His World: A Study of Ecclesiastes, 3rd ed. (Shocken Books: New York, 1968), 76.