I almost never rate textbooks, but this one is different. Now I don’t think it is the perfect guide to all poetry, I don’t think it’s trying to be that. Poetry can be hard to get into. That is there is a sense of intentionality and attention to detail that is more or less absent from prose. There are lots of tools in poetry, chiasmus anaphora and all that jazz. This is a great place to start developing this type of knowledge. Ideally you’ll read this and seek out more, but even this alone provides an understandable and generally comprehensive view of the building blocks of poetry.