The book of Ecclesiastes is a fascinating book both to Christians and non-Christians. Including (and especially to) atheists. The following are some resources on the book of Ecclesiastes from the Christian perspective. But before the links, here's a YouTube video of The Byrds singing their hit song based on Ecclesiastes.
Turn! Turn! Turn! by The Byrds
(Live version opens in another tab by clicking HERE)
R.C. Sproul's Five Part class [audio] lessons on the book of Ecclesiastes
R.C. Sproul's audio lecture on the book of Ecclesiastes from his Dust to Glory series.
[See also my blog on Sproul's series Dust to Glory HERE]
Monergism.com's mp3s on the book of Ecclesiastes
Monergism.com's Sermon Manuscripts and Commentaries on the book of Ecclesiastes
The Linguistic Evidence for the Date of "Ecclesiastes" by the late G. L. Archer, Ph. D.
"Everything Is Vapor": Grasping for Meaning Under the Sun by A.B. Caneday
The Message of Ecclesiastes - Living Presently by Paul Helm
Ecclesiastes and the New Testament by Paul Helm
Alister Begg [audio] sermons on Ecclesiastes
Kenneth L. Gentry sermons on Ecclesiastes
Nigel Styles Video Interview on Ecclesiastes (15 min)
Ecclesiastes by Charles H. Welch (pdf or html)
(This work is instructive despite Welch's Hyper-Dispensationalism)
There are many sermons/lessons/lectures on the the book of Ecclesiastes at the SermonAudio website. Here's a sample of such sermons and series of sermons.
David Silversides series on Ecclesiastes
Philip Ryken series on Ecclesiastes
Ecclesiastes: The Joy of Life by Joe Morecraft III
Ecclesiastes by Dan Olinger (from his series Apologetics: Answering Seekers)
Sample of blogs on Triablogue that directly or indirectly touch on
the book or themes of Ecclesiastes
Biblical "fatalism"
The gathering darkness
Vanity of vanities
Solomonic authorship of Ecclesiastes
Time, like an ever-rolling stream
The race is not to the swift
The Last Enemy
The Dark Night of the Soul
The seasons of life
All good things must end
The world is not enough
Some Classic Commentaries on Ecclesiastes
John Gill's comments on the book (or HERE)
Jamieson, Faussett & Brown comments on the book (or HERE)
Adam Clarke's comments on the book (or HERE)