Aristotle & Samuel Henry Butcher 
Poetics of Aristotle 

pub One.info present you this new edition. I propose to treat of Poetry in itself and of its various kinds, noting the essential quality of each; to inquire into the structure of the plot as requisite to a good poem; into the number and nature of the parts of which a poem is composed; and similarly into whatever else falls within the same inquiry. Following, then, the order of nature, let us begin with the principles which come first.