[This bibliography contains only the more helpful commentaries on Ecclesiastes and ones with which I am personally familiar. I have placed an * after those books that I would recommend you purchase.]
Bridges, Charles. A Commentary on Ecclesiastes. Carlisle: Banner of Truth Trust, 1981 [1860].
Garrett, Duane A. Proverbs, Ecclesiastes, Song of Songs. The New American Commentary. Nashville: Broadman Press, 1993. *
Goldberg, Louis. Ecclesiastes. Bible Study Commentary. Grand Rapids: Zondervan, 1983.
Gordis, Robert. Koheleth - The Man and His World: A Study of Ecclesiastes. New York: Schocken Books, 1973.
Hengstenberg, Ernest W. A Commentary on Ecclesiastes. Minneapolis: James and Klock Christian Publishing Co., 1977 [1869].
Hubbard, David Allan. Beyond Futility: Messages of Hope from the Book of Ecclesiastes. Grand Rapids: Eerdmans, 1976. *
Kaiser, Walter C. Ecclesiastes: Total Life. Chicago: Moody Press, 1979. *
Kidner, Derek. A Time to Mourn, and a Time to Dance. The Bible Speaks Today. Downers Grove: IVP, 1976. *
Leupold, H. C. Exposition of Ecclesiastes. Grand Rapids: Baker Book House, 1952.
Longman III, Tremper. The Book of Ecclesiastes. Grand Rapids: Eerdmans, 1998. * (Be it noted that Longman denies Solomonic authorship)
Swindoll, Charles R. Living on the Ragged Edge: Coming to Terms with Reality. Waco: Word Books, Publisher, 1985. *
Wright, J. Stafford. Ecclesiastes. The Expositor's Bible Commentary. Vol. 5. Grand Rapids: Zondervan, 1991. *
Survey Works on the Poetic/Wisdom Books
Aside from the many commentaries on the individual OT books, there are six introductions to the poetic/wisdom literature that are worthy of note:
Berry, Donald K. An Introduction to Wisdom and Poetry of the Old Testament. Nashville: Broadman & Holman Publishers, 1995.
Bullock, C. Hassell. An Introduction to the Old Testament Poetic Books. Chicago: Moody Press, 1988 [1979]. *
Bullock, C. Hassell. Encountering the Book of Psalms. Grand Rapids: Baker Academic, 2001. **
Crenshaw, J. L. Old Testament Wisdom: An Introduction. Atlanta: John Knox Press, 1981.
Kidner, Derek. The Wisdom of Proverbs, Job & Ecclesiastes. Downers Grove: IVP, 1985. *
Murphy, Roland E. The Tree of Life: An Exploration of Biblical Wisdom Literature. Grand Rapids: Wm. B. Eerdmans Publishing Co., 1996 [1990].