Definition:
Exposition is a statement or type of writing which intends to give information about (or explanation of) an issue, subject, method, or idea. Exposition is one of the four traditional modes of discourse.
"In exposition, every statement is offered as a matter of accepted fact. In argument, only some statements are offered as matters of fact, and these are given as reasons to make us believe assertions or claims." (James A. W. Heffernan and John E. Lincoln, Writing: A College Handbook, 5th ed. Norton, 2000)
"Where questions of style and exposition are concerned I try to follow a simple maxim: if you can't say it clearly you don't understand it yourself." (John Searle)



Exposition as a writing mode:
Expository writing is a type of writing where its purpose is to inform, explain, describe, or define the author's subject to their readers. Exposition goes beyond description to help the reader understand with greater clarity and depth of ideas and thoughts of the writer. Expository writing, like descriptive writing, is commonly found in newspapers, magazines, books, and most other forms of written communication. Expository writing may include elements of narration, description, and argumentation, but unlike creative writing or persuasive writing, its goal is to deliver the information about an issue, subject, method, or idea. Expository text is meant to deposit information and is the most frequently used type of writing by students in colleges and universities. Expository writing often has the information about the events that happened before the story begins. It is often the very first part of the plot and it may also be the background information of the characters and settings. For example, when Cinderella was very young, she lives in a happy life. Then one day, her mother died. Soon after that, Cinderella’s father married a woman who had two daughters of her own. Cinderella’s stepmother and stepsisters were very unkind to her. The stepmother gave her daughters, Lottie and Dottie, fancy dresses and wonderful toys. She gave Cinderella nothing.
In a well-written exposition essay, it remains focused on its topic and lists events in its chronological order. An example of expository writing includes driving directions and instructions on performing a task. Words such as first, after, next, then and last usually signal a sequential writing.


My references:
[[txfile:platformres:MsgMgr\msgmgr.htm|http://www.arcanum-butler.k12.oh.us/Expository_Page.html]]
[[txfile:platformres:MsgMgr\msgmgr.htm|http://www.arcanum-butler.k12.oh.us/Expository_Page.html]]
[[txfile:platformres:MsgMgr\msgmgr.htm|http://dictionary.reference.com/browse/exposition]]
[[txfile:platformres:MsgMgr\msgmgr.htm|http://www.how-to-study.com/study-skills/en/language-arts/18/writing-techniques/index.asp]]
http://www.how-to-study.com/study-skills/en/language-arts/18/writing-techniques/index.asp


Some external links to learn more about expository writing:
http://www.sbac.edu/~idylwild/writingtips.html
http://www.stanford.edu/~arnetha/expowrite/info.html