In the short essay preceding the text of a book, the author attempts to condense the whole of the book and it's inspiration to a few paragraphs. Although often ignored, and rightfully so, sometimes this preface can become something special in itself. In this, "Preface to Lyrical Ballads" (1802) by William Wordsworth, you can sit at the counter and watch the ice cream being scooped out for you:
http://www.english.upenn.edu/~jenglish/Courses/Spring2001/040/preface1802.html
'For all good poetry is the spontaneous overflow of powerful feelings.'
'What I have thus far said applies to Poetry in general; but especially to those parts of composition where the Poet speaks through the mouths of his characters; and upon this point it appears to have such weight that I will conclude, there are few persons, of good sense, who would not allow that the dramatic parts of composition are defective, in proportion as they deviate from the real language of nature, and are coloured by a diction of the Poet's own, either peculiar to him as an individual Poet, or belonging simply to Poets in general, to a body of men who, from the circumstance of their compositions being in metre, it is expected will employ a particular language.'