The following is an excerpt from the forthcoming book “Book Writing for Busy People.” Learn more at www.bookwritingforbusypeople.com.

Writing a book is hard.

Wait… why am I telling you this?

Because if you think that you’re going to sit down at your computer one day, write a complete book in 3 hours and then head off to dinner… you’re going to be very disappointed. Writing a book is not a sprint. It’s a marathon. It’s sitting down every day and writing —even when you don’t feel like it. It’s finishing your book only to find out that the work has just begun. It’s rewarding, don’t get me wrong, it’s just a commitment.

I’m not saying this to scare you. I just want you to understand what you’re getting yourself into. Like anything in life — losing weight, starting a business, moving to a new city— you need to understand your Why and it needs to be a strong enough reason to carry you through the hard times.

So, what’s your why?

Why do you want to write a book? Do you want to share your message with the world and help people? Or do you just think it’ll be cool to talk about cocktail parties?

That first reason is going to burn strong enough in your heart to make you sit down at that computer every day and type your soul out. The second reason… well, let’s just say that you can always talk about what’s going on with The Real Housewives of wherever-they-are-now.

I had a writing teacher a few years ago that said, “We don’t write because we want to. We write because we have to.”

Now that is a Why.

There are some really good reasons to write a book. Let’s take a look at a few of them.

If you are writing a business or self-help book, chances are that you are a speaker, consultant, coach, entrepreneur, business owner, or health practitioner of some kind. You have knowledge to share with potential and existing clients. Assuming that this is the case, you may want to write a book to:

Position yourself as an expert

At some point, you may have been advised to brand yourself as an “expert” rather than a speaker, consultant, author, etc. Those titles are just the delivery method. The expert status means that you have value to give to your clients.

Don’t believe me that writing a book makes you an expert? Would you believe Forbes magazine?

“The ultimate ticket to establishing yourself as an authority. Authors are perceived as instant subject matter experts, which can attract media attention, dazzle clients and prospects, create opportunities for speaking engagements, and so much more.”

See, I told you!

Provide your clients with extra assistance outside of your meetings or sessions

How long have you been in business? How long have you been alive?

Can you communicate everything you’ve learned and everything you have to share with your clients in a 30-minute consultation or a 90-minute planning meeting? Even if you had the time to sit with them and share all of your brilliance, would you want to do that with every single client or potential client that comes your way?

Sell in the back of the room

When you speak, people will want to take a piece of you home with them. (Yes, that sounds creepy. Just roll with it). Just like you can’t share all of your knowledge in a 90-minute planning session, you can’t give all your content in a 45-minute keynote either. Having a book is an inexpensive next-step for audience members to take. Sure, you may be able to sell a $15,000 coaching program from the stage, but it’s not likely with most audiences. However, selling a $20 book is much easier. Not only that, it’s the first step into your sales funnel. If this is a new term, it’s a way of building rapport with potential customers or clients while increasing the amount of money they spend with you.

Leave a legacy for the next generation

I have a friend who started out by writing a letter to his niece and nephew. After the 30th page, he realized that he wasn’t writing a letter. He was writing a book. And his family members weren’t the only ones that could benefit from the wisdom he was sharing. He turned it into a book about how to forge your own path and live a life worth living. His ideal readers are Millenials and it’s selling quite well.

Release the past

You’ve been through something in your life. I’m not psychic, I just know that if you’ve been around for more than a few years, you’ve dealt with some crap. You may still be dealing with it. You may have spent thousands of hours and dollars in therapy, with a coach, a Reiki master, a past life regressionist, and whoever else you thought could help you get past it. I’m not saying they don’t help. I’ve patronized almost every one of those people during my journey. I believe they’ve all had a hand in my healing, but so did I. I journaled, I wrote fictional accounts of my experiences, I incorporated true stories from my life into my books. I used the bad things that happened to create something good; something that helped me release the trauma, and can help someone else overcome their challenges. There is something extremely cathartic about putting your experiences and your emotions down on paper. Yes, it makes them more real, but it also takes away their power to keep hurting you.

These reasons are all part of your Why. But, is there a bigger reason at play? A life’s mission, if you will?

If you’ve read Surviving to Thriving or Once Upon a Bottom Line, or know me personally, you know that I am an animal lover and advocate. I’ve been doing animal rescue for 10 years now and I credit the animals, the activities, and my rescue family with the reason that I’m not in a mental institution right now. All kidding aside, my depression was severe and if it weren’t for volunteering, I’m not sure I’d have survived my past.

Because of this, animal rescue and advocacy is at the core of everything I do. I’ll teach business owners, non-profits, and individuals how to find their voice… but most importantly, I will be a voice for those who cannot speak. A portion of every book I sell and every speaking engagement I do goes to Hearts Alive Village. I have to create. I have to teach. I have to write. Animals are depending on me.

So, I’ll ask again: What’s your why? Do you want to take care of your family? Eradicate homelessness in our country? Support veterans? Protect children? What will get you out of bed every morning and drag your butt to the computer? Find that, and writing will be a breeze.