Eighteenth-century and Romantic readers had a peculiar habit of calling personified abstractions "sublime." This has always seemed mysterious, since the same readers so often expressed a feeling that there was something wrong with turning ideas into people--or, worse, turning people into ideas. In this wide-ranging, carefully argued study, Steven Knapp explains the connection between personification and the aesthetics of the sublime.

Personifications, such as Milton's controversial figures of Sin and Death in Paradise Lost, were seen to embody a unique combination...