Some writers get very specific and their intended audience becomes some like this:

A single Caucasian mother, age 32, three children, owner of a mini-van, listens to light rock and lives in an apartment complex.

You may not need to get that specific, but if you have an age range and can determine if it has a specific gender interest it can go a long way in defining the 'audience' for your book.

The reason this is important has to do with helping you keep your writing on task, but is also useful in demonstrating to a publisher that you have an article or book manuscript that may fit with the demographic needs they have expressed.

The next time you are in a book store take some time to look at the back cover of the book. In the bottom corner you will read such things as Self-Help, Juvenile Fiction, etc. These designations are a means of helping the reader and book store owner understand who the intended audience is for the book. The book store owner can then categorize all such books in one convenient location and the customer can gain easy access to books that are intended for them.

If this amount of detail is put into the marketing side of publishing you can see how important it should be for you, as the author, to define your 'audience'.

It may be tempting to indicate that the book is of 'General Interest", however, a publisher may be equally tempted to simply overlook the work as being too vague to fit their overall objectives.

When crafting a proposal to present to an editor make sure to include information on your 'audience' and why your piece makes a good fit for the audience.

The core idea of the 'audience' is to discover a target so you know where to aim your pen.

This approach tells the publisher that you've done your homework on the subject and how it relates to its intended audience. It provides the publisher with the sense that you are knowledgeable about the subject matter and confident in your ability to connect with the reader.