Ecclesiastes - the Greek rendering of the Hebrew Koheleth, which means "Preacher." The old and traditional view of the authorship of this book attributes it to Solomon. This view can be satisfactorily maintained, though others date it from the Captivity. The writer represents himself implicitly as Solomon (1:12).
So I returned, and considered all the oppressions that are done under the sun: and behold the tears of such as were oppressed, and they had no comforter; and on the side of their oppressors there was power; but they had no comforter.
There is one alone, and there is not a second; yea, he hath neither child nor brother: yet is there no end of all his labour; neither is his eye satisfied with riches; neither saith he, For whom do I labour, and bereave my soul of good? This is also vanity, yea, it is a sore travail.