When people approach me about writing a non-fiction book, my advice often disappoints them because of their expectations about the publishing world.There seems to be a pervading myth that simply publishing a book, on its own merits, is enough to bring fame and fortune to any author. This may come as a surprise, but if your purpose in wanting to write a book is to make money, then read on as I shed some light on the real truths behind book publishing.Very few non-fiction authors make much money from their book alone. Publishing a book and getting nationwide distribution is an exorbitantly, and in most cases prohibitively, expensive process. It’s time and energy intensive, and will take massive amounts of resources.In fact, non-fiction authors will spend anywhere from $400-800,000 before they even break even with book sales (anywhere from 200-350,000 copies sold). So if it’s that difficult and expensive, what’s the point of publishing a book anyway?There are two main reasons to write and publish a non-fiction book, and to make money certainly isn’t one of them. The two reasons are to market your business and to gain credibility.Reason #1: MarketingUnless you have a baseline business platform, other than your book idea, to drive traffic to, there’s very little point in publishing a non-fiction book. You won’t make any money and it won’t be worth the effort. The successful non-fiction authors are those who understand that their book is nothing more than a marketing tool to drive traffic to their business, and who exploit this knowledge effectively.For example, Stephen Covey’s books drive traffic to Franklin Covey, T. Harv Eker has Peak Potentials Training, Mark Victor Hansen and Robert Allen’s book The One Minute Millionaire markets the Enlightened Wealth Institute, Killing Sacred Cows by Garrett Gunderson and myself leads to the Freedom FastTrack process, marketing guru Seth Godin built Squidoo, Ken Blanchard’s company is a global leader in workplace learning and productivity, just to name a few.The real money to be made from publishing a book doesn’t come from the book itself; it comes from the business that the book is designed to market. So what does this mean for you? You should spend far more time and effort developing a legitimate business, rather than writing a book.Besides, you don’t even need to write the dang thing yourself–that’s what guys like me are for. You build your business, and let me get your book written. Your time is much better spent focusing on your business, products, and services. This approach will ultimately result in far more dollars to you than trying to make money from book sales alone.Reason #2: CredibilityIn the Information Age, your audience is drowning in information. They’re constantly bombarded with television, radio, books, advertising, Internet, blogs, music, etc. So why should they listen to you, especially when there may be countless competing factors sending them conflicting messages? When faced with information overload, people listen to and buy from those they deem to be credible.Think about it: why are quotes so powerful? It’s not because of what is said in a quote that makes it relevant and important to you–it’s because of the credibility of the person saying it. When you hear the words, “Be the change you want to see in the world,” the quote sticks with and impacts you not because of the actual words, but because you know they came from Gandhi, a man who earned ultimate credibility on the subject of changing the world. Your neighbor could say the same thing, but unless he has credibility on that subject, the words will impact you far less and you will quickly forget them.The phrase “Imagination is more important than knowledge” could be seen as nothing but a trite adage, but coming from the mind and mouth of Albert Einstein, it carries substantial weight and meaning.Credibility is a precious commodity in the business world, and it’s one that, once gained, will dramatically increase your bottom line. There’s something about being a published author that gives a person instant credibility. Imagine being at a party and meeting three new people. Suppose the first two people you meet are incredible businessmen (or women), and the third is actually far less accomplished than the first two. But if you learn that the third is a published author, suddenly you pay more attention and give more weight to their words. And the chances are high that the published author, despite any of their other accomplishments, is the one that you will remember months later.ConclusionIf you are thinking about writing a non-fiction book, my advice is that you must first understand that publishing a book is not a good way to make money in and of itself. You absolutely must develop a world-class business that the book is deliberately designed to market, and it’s through increasing traffic to this business that you will make your real money. And by gaining credibility, which comes from being a published author, the chances of getting people to consistently buy from your business are considerably greater.In other words, what you need isn’t a good idea for a book, but rather, a good business to market.