Now that we’ve started you off with the basics of authoring, let’s continue to part two and try to visualize you, the author as the CEO and business owner…

You’ve created the product (wrote the book)
You are now a company (Sole proprietorship) and your company is responsible for not just having created the product, but branding your company, marketing your product and eventually selling your product.
Your begin marketing your product by getting it to your first customer (the editor)
They take a look at your product and decide whether or not it needs revising or is ready for mass selling.
If the customer likes what you’ve created, they begin spreading the word (talking to the publisher)
The publisher is now your second customer
They also decide whether to buy (accept your product) and how much to pay you for your product (advance)
If thye like your product and have bought it, then they begin spreading the word (marketing your product and you the business owner)
Eventually, word gets around and not only has the editor and publisher become your customers, but so have the Internet visitors, bookstore visitors, or grocery store shopper.
Now let’s say you are working with a freelance editor, not necessarily associated with the publishing house, the point still remains that they are your first customer. An agent is not your customer, but your business partner. Regardless of where and who the editor works for, after receiving and reviewing your product, they will spread the word. Either to a friend or via their resume (I edited so and so’s manuscript).
The agent is your business partner. They get a cut of your profits (80/20) once your product is out on the market. As a business owner, know that having a partner works as long as you two are on the same page.
But isn’t a customer someone who buys something from you?
Not necessarily. First of all, not every editor gets paid as some do editing for free. Second, even if they are paid, in the business world a customer is Customer – Groups or individuals who have a business relationship with the organization–those who receive and use or are directly affected by the products and services of the organization. Customers include direct recipients of products and services, internal customers who produce services and products for final recipients, and other organizations and entities that interact with an organization to produce products and services. [GAO]-http://www.ichnet.org/glossary.htm.
Another way to look at it is this: When a company gives you a gift card worth a certain value ($25, $50,etc)for example or even wants you to participate in a focus group, they pay you. You are the companies customer (gift card) and you are going to be the buyer or customer that helps make the product better (focus group). Paying your customer is sometimes the cost of doing business.
As you can see, being an author is serious business, but it is indeed a business. Thinking of it this way should make it easier for you to not just create a brand for yourself, but market your product and the company behind it (you).