One obvious selection would be Okla Hannali. After the DAPL protests, a lot of focus has been placed on Native American issues. Okla Hannali is one of the greatest novels of the 20th Century. I firmly believe the U of O Press are among the genuinely good guys of the world, and I love the edition they publish. What I'd like to see is full-court press to get their edition advertised better, placed on the bookshelves of major chain bookstores under American Lit or Native American stories, and first and foremost urged into American Studies curriculums across the country. I really think this country could become a better place if more people read that book.
That being said, I have a different recommendation for the next Lafferty novel. Fourth Mansions feels more relevant today than it did when it was written. There is a feeling in today's world that things are not what they seem. That we are on the verge of greatness or breakthrough and being prevented by forces beyond both our control and our understanding. Ultimately, Fourth Mansions is a very hopeful book--full of the promise that we common everymen, we everylouts can master the monsters that beset us and bring about the next step in our collective development. It is a variation of the hope that The Once and Future King and the Harry Potter books offered--the hope the each of us could secretly be the chosen one, the one capable of leading humanity to success. However in Fourth Mansions though the gifts fall to Freddy Foley, he stands in for every one of us. The power is available to all people, not restricted to a single chosen one.
It'd have been great if Fourth Mansions could have been re-released when the fever over the Dan Brown book was at its peak, because the world could have seen how the conspiracy story could have been told in far greater depth with far greater economy, skill, and joy. Still, in today's political and media climate with bogus conspiracy theories du jour cropping up left, right, and far right, Fourth Mansions might feel spot on.
I'd love to hear everyone else's suggestions.