The title Ecclesiastes given to this book is the Greek translation of the Hebrew name Qoheleth meaning, perhaps, "one who convokes an assembly." The book, however, does not consist of public addresses, but is a treatise, more or less logically developed, on the vanity of all things. Reflections in prose and aphorisms in verse are intermingled in Ecclesiastes, which contains, besides, an introduction and an epilogue.
The book is concerned with the purpose and value of human life. While admitting the existence of a divine plan, it considers such a plan to be hidden from man, who seeks happiness without ever finding it here below (Eccl 3:11; 8:7, 17). Ecclesiastes applies his "Vanity of vanities" to everything "under the sun," even to that wisdom which seeks to find at last a semblence of good in the things of the world. Merit does not yield happiness for it is often tried by suffering. Riches and pleasures do not avail. Existence is monotonous, enjoyment fleeting and vain; darkness quickly follows. Life, then, is an enigma beyond human ability to solve.
while Ecclesiastes concedes that there is an advantage for man in the enjoyment of certain legitimate pleasures lest he lapse into pessimism and despair, he nevertheless considers this indulgence also vanity unless man returns due thanks to the Creator who has given him all. Under this aspect, earthly wisdom would rise to the higher level of true spiritual wisdom. This true wisdom is not found "under the sun" but is perceived only by the light of faith, inasmuch as it rests with God, who is the final Judge of the good and the bad, and whose reign endures forever. The Epilogue gives the clue to this thought (Eccl 12:13, 14).
The moral teaching of the book is imperfect, like the Old Testament itself (Hebrews 7:19), yet it marks an advance in the development of the doctrine of divine retribution. While rejecting the older solution of earthly rewards and punishments, Ecclesiastes looks forward to a more lasting one. The clear answer to the problem was to come with the light of Christ’s teaching concerning future life.
The author of the book was a teacher of popular wisdom (Eccl 12:9). Qoheleth was obviously only his literary name. Because he is called "David’s son, king in Jerusalem," it was commonly thought that he was King Solomon. Such personation, however, was but a literary device to lend greater dignity and authority to the book-a circumstance which does not in any way impugn its inspired character. The Epilogue seems to have been written by an editor, probably a disciple of Qoheleth. The entire work differs considerably in language and style from earlier books of the Old Testament. It reflects a late period of Hebrew, and was probably written about three centuries before Christ.