It is a collection of the sayings of an anonymous wise woman (or man), who is known as the Teacher, or the Preacher.
I am never sure as to whether the Teacher is a cynic or a realist, but I am glad for her rich and poetic imagery as she meditates on the vanity (pretentiousness?) of life in the face of death.
I especially admire the poetic allusions as they are rendered in the Authorized/King James Version of the bible.
Here is the text:
Here are some more detailed notes ("lifted" from the web)
2. Illustrating "the evil days" ( Jeremiah 13:16 ). "Light," "sun," &c., express "darkness," ( Isaiah 13:10 , 30:26 ).