You can pick up the core ebook Lucid Immersion Guidebook at the ebook retailer of your choice.
Amazon.com (US) — for Kindle and Kindle apps (for PC, mac, and all smartphones). You can also search for the title on Amazon stores around the world.
Barnes and Noble.com — for Nook readers and Nook apps (PC, mac and all smartphones)
iTunes.com — for iBook readers (mac and iPhone, iPad and iPod)