How Natasha Trethewey's Chapbook Thrall Begins

I just found the following quotes as the introduction to the chapbook called Thrall, which was written by Poet Laureate Natasha Trethewey:

What is love?
One name for it is knowledge.
    --Robert Penn Warren. 

After such knowledge, what forgiveness?     --T.S. Eliot.

What a beautiful beginning to a poet whose work I had not yet read!

I haven't much to say yet about the work that is inside. To be honest, I stopped at the quotes. While I understand the quotes have other significance in context, they also have significance to me without their context. Further, the quotes bring together two of my favorite poetry forms which are the found poem and exquisite corpse.