What is the author's style in The Surrender Tree: Poems of Cuba's Struggle for Freedom by Margarita Engle?

The language of this book is written in poetry form but, in general, without any sort of rhyming or other pattern. Each poem is essentially a short essay from the view point of one of the characters. The language is quite simple, since it is a book for children. Although the language is simple, the story makes a big impact on the reader.