Have you ever wondered if there were rules governing the use of dashes in English writing? Well, of course there are! Doesn't the English language have a rule for every little thing?

"But it's just a dash; how can there be proper and improper ways to use it?" you ask.

Guess what? It's not just "A" dash, singular. There are actually several types of dashes used in writing. Our concern is with the two most commonly encountered: the em and en dashes. The em dash gets its name because it's the same width as a capital "M"; the en dash is the same width as a lower case "n".

And each has its own special set of functions, too. Before you throw up your hands in confusion and disgust, let's quickly examine the uses of each type of dash. It's really not as complicated as you'd think.

Let's start with the en dash. You'll most often see it used to express a numeric range of some sort: "The event is scheduled for June 5-7," or "Read pages 415-465 for tomorrow." There is no space between the dash and the numbers surrounding it.

The em dash, however, is quite a versatile little thing. It can be used to indicate an ongoing occurrence, as on a resume, where one might list "Computer technician, XYZ Corp., 1998-." This lets the person seeing the resume know that you're still employed with XYZ Corp.

It can also be used to set off a related but somewhat tangential thought in a sentence: "And when she came in, she was wearing orange-you know, some people can get away with orange but I can't-pants and a cowboy hat!" Notice that, just as with the en dash, there is no space between the em dash and the phrases on either side of it.

The em dash can also be used to separate a list from the main thought in a sentence: "His few belongings-a few items of ragged clothing, a worn copy of Tom Sawyer, an autographed photo of Marilyn Monroe, some faded posters and a bundle of letters tied together with a piece of twine-were found in the near-empty apartment."

If you're writing dialog, the em dash can be used to indicate an interruption in thought or speech:
"I was just going to say-"

"Oh, be quiet! No one wants to hear it!" snapped George.
Or:
"I don't-hold on-how did-oh, I just don't get it!" moaned Nancy.
The em dash can also be used for emphasis: "The warranty is certainly valid-if you didn't remove the tag."

In the pre-computer world, em dashes were indicated on typewriters by typing two hyphens; in most modern word processing programs, typing two hyphens with no spaces between them and the surrounding words will cause the program to automatically convert the double hyphens into an em dash. Below I've taken one of the previous examples and put spaces between the hyphens and the surrounding words and then eliminated the spaces so you can see what I'm talking about:

His few belongings -- a few items of ragged clothing, a worn copy of Tom Sawyer, an autographed photo of Marilyn Monroe, some faded posters and a bundle of letters tied together with a piece of twine -- were found in the near-empty apartment.

See how the double hyphens remain with improper spacing? Now, let's remove the improper spacing again:
His few belongings-a few items of ragged clothing, a worn copy of Tom Sawyer, an autographed photo of Marilyn Monroe, some faded posters and a bundle of letters tied together with a piece of twine-were found in the near-empty apartment.

A word of warning, however: Em dashes are used sparingly in academic or formal writing, as they're really a little informal for such works. That's not to say that they absolutely cannot be used, just that you don't want to litter your paper with them. A few well-placed em dashes won't hurt, but if you're using them several times on every page, you've probably overdone it. That actually applies to any kind of writing, in fact. Use em dashes judiciously in all your written material.

If you're still not sure about the use of dashes, why not let the professional editors at Book Editing Services make sure you're using them correctly?

www.firstediting.com offers invaluable editing tips for both fiction and non-fiction writers, students preparing thesis and dissertations, and business people creating marketing documents.

Ms. Todd is an award-winning, full-time professional editor, published writer and marketing consultant whose passion is to help others create a letter-perfect presentation in their writing. Her extensive experience in coaching and management has allowed her to independently consult for numerous international editing services and websites.