I first read this years ago, and though I was enjoying poetry at that point, I had yet to really appreciate it. This little book is what got me going.
Bly explores the influence of culture and language upon approaches to poetry, and offers poems from Spain, Japan, Sweden, Germany and America to show the kinds of imagery and sound that make for evocative and provocative leaps of imagination. Because that's what poetry is all about for Bly: leaps of imagination, of association, among images and sounds and ideas and emotions, all of a piece. Grasped and felt intuitively. Conscious, or cognitive, understanding of the poetic is always secondary to what is evoked.
A sample of his critique that broadened my thinking and appreciation:
"It's odd how seldom American poets or critics mention association when they talk of poetry. A good leap is thought of as a lucky strike if it appears in the poem, wonderful!; but if not, no one thinks the worse of it . . . We accept tons of dull poetry, and no one looks for an explanation of why it is dull. We are not aware of association . . . The early poems of Wallace Stevens are some of the few poems in English in which it is clear that the poet himself considered association to be a form of content."