UPDATE: The Kindle Unlimited run for 20 Million Leagues Over the Sea has ended.
However, the book is still available on Amazon in both ebook ($2.99) and print form ($12.99).
The ebook is now available at Smashwords for the same low price. Smashwords offers ebooks in various formats, including Kindle, Nook, Kobo, and more!
To celebrate my return to Smashwords, I am offering a coupon: get the ebook there for free with coupon code ME46H thru June 1, 2018!