You should write a book. It just may not be for the reasons you think.
The quickest way to get started in the information business is by doing an audio interview. Do a quick outline or put together a few questions. Find an expert. Record an hour interview. You now have a product. No more than 2 hours were invested in the process...and a minimum amount of money (a simple phone recording device can get you started).
A book takes at least a week to write, and you have to pay for a well designed cover to sell it. Yet, I still recommend a portion of my clients create a book. Why?
It's simple really. Becoming an author provides you with immediate benefits that are hard to compete with in any other way.
1. Improve Credibility for Consultants and Coaches
If you're currently doing any consulting or coaching, having your own book separates you from the competition. Would you rather hire the consultant who studied all these books...or the author of the books they studied?
Instead of simply giving someone your business card or a brochure, you can hand them your book. You're the expert. While most people won't "read" your book, it now goes on their shelf with other books they've purchased. It makes them feel better just having it.
2. Increase Fees
Want to increase your fees? Publish a book. This one goes right along with number one. You've improved your credibility, so you can now raise your rates. This includes consulting, coaching, and speaking fees. You're a busy author (doing publicity campaigns and more). Your time is valuable.
You'll also run into less price resistance as an author. It seems miraculous, but your perceived value in the eyes of your clients has now went up. You're an author...and your "expert" fees seem more reasonable now.
3. Generate Publicity
Send out review copies. Do radio talk shows. The media is starved for good interviews. You now have something to talk about in your new book (I recommend creating your book with publicity in mind from the beginning).
Not very many people will listen to an interview and hire you to consult with them. They will buy your low cost book and be added to your customer list. Then you can follow up on them with all your higher profit items on the backend.
4. Backend Sales
A book is a perfect entry point in your product funnel. Let's say you sell DVDs, home study courses, and even do workshops. Your higher price point items might require an endorsement from a trusted source or someone to speak to them on the phone. The book simply has be offered as a solution to a problem they're having. It's an easy sale.
You can then have upsells and other offers throughout the book. Don't turn the entire book into a sales letter. DO offer items that solve their problems. The book can be a doorway into your other product offers.
5. Deepen Your Knowledge Base
Even if you never sold a copy, a book can still be profitable to you. It requires you sit down and organize your thoughts. You have to outline. You have to study your subject more in depth. You'll have a broader base of knowledge and skill when you're finished with your book.
To put it simply...writing a book will help you grow. It will stretch you. You'll come out of it with greater knowledge, experience, and value to give to others.