I wanted to finish Leigh Brackett's Skaith Trilogy (The Ginger Star, The Hounds of Skaith, The Reavers of Skaith) before writing about it, but The Hounds of Skaith is so well-written I need to unload right now before my brain swells up.
Here's the situation: our hero is Stark, a Tarzan-like wild man raised in civilization to be a sort of interstellar troubleshooter for an ersatz United Federation of Planets. With his mentor kidnapped, he visits the dying low-tech world of Skaith. The world's rulers, fearing his presence will overthrow the existing order, attack Stark in a way that begins unraveling the world's existing order.
Having slain the leader of a pack of psychic wolves whose powers only he can withstand, Stark asserts dominance over the wolves as he races back to the planet's only starport, which is located deep within the territory of the planet's rulers and his enemies--the Wandsmen.
Now, here's the clever thing. The psychic wolves exist to protect the Wandsmen and will not harm them. They serve Stark (he is Strongest, so they follow), and they do not necessarily serve the Wandsmen, but every time Stark fights the Wandsmen's allies, his control over the wolves erodes a bit more. Yet he cannot abandon them--their mind-reading powers have already saved his life more than once, even as they articulate a growing dissatisfaction that will, it's obvious, culminate in the same challenge for dominance that let Stark take control of the pack. They are simple creatures, and cannot comprehend Stark's goals and actions, and each encounter with the Wandsmen pushes the pack closer to a betrayal that is not really a betrayal at all--more of a return to the creatures' natural existence.
This structure reminds me of good modern television: the system is inherently unstable, and now the writer's job becomes to shove the hero from every direction until everything falls apart. I never really understood the writer's adage "put your hero in a tree and throw rocks at him" until I saw the trick used here. This is the exact opposite of Marvel-style comic book writing--where the trick is to produce a dynamic-seeming situation that always springs back to normal--and reminds me of Steven King, where you know the bad stuff is coming (you know from The Shining's first interview scene that Torrance is going to go after his kid, Danny, with an axe), but you don't know when it's coming.
Adding to the drama is the realism of everyone's motivations: Stark just wants to escape Skaith, the wolves are beasts who cannot change their natures, and the Wandsmen are portrayed as sympathetic antagonists who can no more fathom what Stark represents than the wolves can. There are no "villains" here, only agendas that cannot be brought into harmony.
And through that tension Brackett weaves a thrilling action story. The situation's inherent instability lends excitement to what, in lesser novels, would just be a bunch of "random encounters": here's Stark fighting cannibals, okay; here's Stark facing a sandstorm. Even today many SF/F novels still rely on a picaresque structure like this (when they're not cut-and-pasting the plot of Star Wars). The best writers (Jack Vance, Poul Anderson) bring their worlds and characters to life with such skill that they don't need the dynamic instability of a plot like Hounds of Skaith's, but most lesser writers don't bother, and their stories are just one damn thing after another. Brackett understands how to combine picaresque encounters with unstable dynamic situations in a way that creates a story that is both exciting and nail-biting. So far the Skaith trilogy has been an exhausting, thrilling read.