"Kalin" is an Ace Double written by E.C. Tubb, and published in 1969. The flip side of the book was The Bane of Kanthos. The book was also the fourth part of a 33 book series, the Dumarest Saga, that was published over a 50 plus year time frame, from 1967 to 2010. The scope of the background story was not known to me when I read this book, although after finding out that this book was part of an extensive saga, the richness of this book made a lot more sense.
"Kalin" takes place in a far future science-fiction universe that is slightly above dystopia. Humanity is scattered among countless warring worlds, and the knowledge of earth is lost. The protagonist, Earl Dumarest, remembers being from earth, and is travelling the galaxy trying to find his home. All of this is background information: the story itself centers around Dumarest finding the titular Kalin, a young woman with telepathic powers, on the run from people about to execute her as a witch. They travel the universe together, and through happenstance, end up on a bleak, frigid mining planet where they have to hunt dinosaurs to avoid becoming slaves. Meanwhile, Kalin's true identity is a mystery, one sought after by the Church of Universal Brotherhood. There is a lot going on here, along with asides philosophical and sociological.
Ace Doubles were known for editing strictly to fit the page requirements. They were also known for being garish and brief. And yet, this book presented a layered, intricate story inside of 130 pages, and still had time for exploding spaceships and charging dinosaurs. I find it an especially interesting comparison next to the flip side book, The Bane of Kanthos, that while having an involved map and narration, didn't manage to feel like it had a real backstory or immersive world. Being able to quickly and efficiently immerse the reader into a complicated world is one of the things that a good science-fiction writer can do, and after reading "Kalin", I want to read much omre of Tubb's series.