Both domains are very important. I suggest that you use both of them in different ways.

If you believe that your empiric spirit domain is a "company" that you would like to support in social media and in articles, etc., for years to come, support it on its own domain separately from your personal domain.

However, I surmise that your personal domain is where you will (and, in my opinion, should) be driving up your social media presence and content. So, I recommend that you direct all book traffic there.

So, create a subdomain for your site, or a subfolder, and "point" your book domain to that subfolder. Write about the book in your social media and blog, and all traffic will come where you want it to ultimately come - your website.

It's important to maintain a website for the success of your book - for informational purposes, and to show people where to purchase the book. But it is important that you use social media like a pro, and become a guest blogging expert and frequent guest on radio programs... Those things matter much more. Direct all traffic where you want using bitly links, and track what is most effective.

Good luck! Enjoy the journey :)

Great questions Matt. I always recommend the personal branded domains for writers. Oftentimes we as the creators of our projects, brands and books find a theme to be a unifying or grounding force ourselves, but I've found that they usually do little to help forge any sort of connection or bond with potential readers. The personal brand (your name/face, and thus, your story/context) is what allows an otherwise anonymous prospective reader online connect with you on a deeper human level -- the human connection is always more memorable than a brand name or theme.

Also, you have the practical flexibility of using the same brand name for the rest of your life (unless you become a felon! :), whereas you might creatively outgrow EmpiricSpirit someday! I'd recommend the personal branded domain.

I did both (jamienotter.com and humanizebook.com), though that was for just one book. And I already had a consulting business on my own, so both sites are both different and necessary. To some extent it's a duplication of effort, but once the books are out there you'll start to see which site is really getting the attention and energy and then further develop that one.

It depends on your long term plans/goals. Assuming that you have aspirations beyond the three books, I would save your personal branded domain for your blog, bio and other information. Use your other domain name for the books. Of course you can link back and forth between them. If the books take off and you want to keep conversations about the books separate from other stuff, it would be hard to do on your own domain name down the road. Though it is a pain to develop and maintain multiple sites, if I was writing books, I would want them to be on their own domain.

I spent 6 years marketing myself as a website designer, then focused more on marketing myself as a photographer for about 5 years and then switched back to focusing on web again. This has been an easier process because I had individual sites for both web design and photography. My own personal domain name was always kept separate and is a collection of my ambitions and life over the years.

In the end, do what you feel best represents what you are about and how you feel the books will be best marketed.