Seven Types of Ambiguity (Empson)
Seven Types of Ambiguity was first published in 1930 by William Empson. It was one of the most influential critical works of the 20th century and was a key foundation work in the formation of the New Criticism school. The book is organized around seven types of ambiguity that Empson finds in the poetry he criticises. The first printing in America was by New Directions in 1947.
Seven Types of Ambiguity ushered in New Criticism in the United States. The book is a guide to a style of literary criticism practiced by Empson. An ambiguity is represented as a puzzle to Empson. We have ambiguity when "alternative views might be taken without sheer misreading." Empson reads poetry as an exploration of conflicts within the author.
Seven types 
- The first type of ambiguity is the metaphor, that is, when two things are said to be alike which have different properties. This concept is similar to that of metaphysical conceit.
- Two or more meanings are resolved into one. Empson characterizes this as using two different metaphors at once.
- Two ideas that are connected through context can be given in one word simultaneously.
- Two or more meanings that do not agree but combine to make clear a complicated state of mind in the author.
- When the author discovers his idea in the act of writing. Empson describes a simile that lies halfway between two statements made by the author.
- When a statement says nothing and the readers are forced to invent a statement of their own, most likely in conflict with that of the author.
- Two words that within context are opposites that expose a fundamental division in the author's mind.
Popular culture citations 
- Shirley Jackson penned a short story of the same title, in which a young man who frequents a used bookstore admires Empson's book but can't afford it.
- Melbourne author Elliot Perlman's 2003 novel Seven Types of Ambiguity takes its title from Empson's first book. Empson is the intellectual hero of the book's protagonist, who names his dog accordingly.
- In the 1968 film adaptation of The Magus, one of the books in the protagonist's luggage is The Seven Types of Ambiguity
- A copy of this book is one of the objects in Leanne Shapton's 2009 book Important Artifacts and Personal Property From the Collection of Lenore Doolan and Harold Morris, Including Books, Street Fashion and Jewelry.