This book seems a sort of stepping stone for everyone who thinks that close reading is for the classroom, and that poetry analysed loses its beauty. As Eagleton shows, good poetry appears more beautiful when it is read carefully and sensitively, by a reader who has some prosodic apparatus for approaching a text. It makes a case for why we should learn to read poetry with an ear (and an eye) that is sensitive to poetic form, even if we don't have an essay to hand in at the end of the week, and gives us a demonstration of how to be sensitive to poetic form.
Eagleton starts his book with the idea that overemphasis on cultural theory has led to a decline in interest in the skill of reading sensitively and perceptively. I might be inclined to agree with him - extensive teaching of prosody and poetics etc is not regarded as being as important in academic circles as it was a few years ago. However, his point that an interest in cultural theory does not preclude an active interest in close reading and textual analysis is a fair one.
Eagleton sets out on a survey of the ideology and practicalities of poetry reading, with sections on 1) the function of criticism, 2) defining poetry, 3) ideas of the schools of formalism, 4) the relationship between form and content and 5) some of the issues involved with reading poetry (tone, mood, syntax, metre etc). The final section puts the theory into practice, and looks at four nature poems.
If the book is not extensive in terms of its covering the many aspects of poetry reading, neither is it limiting. At no point does Eagleton claim to give a exhaustive account of poetic techniques or the discipline of reading, rather the book functions as a demonstration of the benefit of informed close reading of poetry for pleasure or study. If you want a more extensive study of prosody, and poetics etc, then a dictionary of poetics like the 'New Princeton Encyclopedia of Poetry and Poetics' would probably be more up your street.