I've been eagerly waiting for 'Quantum Earth Book 3' too, and I found it on Amazon. The paperback version is available, and you can also get the Kindle edition if you prefer digital. The price is reasonable, and the delivery is pretty fast if you have Prime. I’ve bought the first two books from there, and the quality was great. You might also want to check out Barnes & Noble’s website, as they sometimes have exclusive editions with extra content. If you’re into audiobooks, Audible has it narrated by a fantastic voice actor, which really brings the story to life. I’d recommend checking multiple platforms to see which one suits your preferences best.