"Limbo," by Bernard Wolfe, is available on pre-order from Amazon for $6.99, and will be published as a Kindle ebook on April 14, 2016. Here's the link:
http://www.amazon.com/gp/product/B01...=sr_1_2&sr=8-2
This is an important book, one that I read way back in the early '70s. It was published in 1952.
I've already pre-ordered my copy.
It would make a great book for discussion here at Mobileread, due to a number of controversial topics.
Check out some comments at Goodreads:
http://www.goodreads.com/book/show/636193.Limbo