Just what is 'vanity'?

Editor's note: Ray Waddle reflects on the question in this excerpt from his book, Against the Grain: Unconventional Wisdom from Ecclesiastes (Upper Room Books, 2005).

“I hated all my toil in which I had toiled under the sun, seeing that I must leave it to those who come after me—and who knows whether they will be wise or foolish? Yet they will be master of all for which I toiled and used my wisdom under the sun. This also is vanity”(Ecclesiastes 2:18-19).

The word vanity, hebel, continues its march across the pages [of the New Revised Standard Version]. Other modern translations replace “vanity” with up-to-date words, trying to get closer to the intended meaning. Instead of “This also is vanity,” other recent translations say “This too is meaningless” or “This also is futile” or “This too is emptiness.”