I was struck by these lines from that preface:
My definition of a good poem is that it appears before you like a stranger who impresses you so favorably that you feel like befriending him, and the more you know him the more you like him.
...and responded thus on the blog:
My own experience of poetry focuses less on friendship than on the other trope your father so astutely introduced here, namely that of the stranger. The good poem is the stranger who is never wholly reducible to friendship, it retains something in reserve. And perhaps a better way for me to approach your father’s thought is by recognizing that he sets up two axes, two poles, here: the friend and the stranger; and it is between these two that poetry happens.