Poetry is a violently opinionated business. The closest I have come to a civil war was – quite seriously – a conference on versification. Poetry lovers, however, tend to be polite people who express their feelings in convoluted ways. Hence, perhaps, their love of poetry, but also the incoherent quality of much poetry criticism.

Glyn Maxwell, a British poet, begins On Poetry by going back to Shakespeare. In doing so, he concedes what might be called the anthological paradox. The great poets of the past are, largely, agreed. Yet the canon does not lead to present-day consensus, a problem Maxwell finds exacerbated by literary