The Alastor trilogy opens with Trullion. An extremely fast-paced story, it tells of Glinnes and his return to his home planet after ten years in the galaxy's police force. Far from the prodigal son, he returns to broken circumstances: one brother is missing, presumably murdered, his other brother has sold the family estate, his sister is carefree, and his mother no longer has any interest in the family. To top it all off, there doesn't appear to be any way to get the estate back, and there is a troupe of gypsies camped in their back lawn that don't want to leave. Getting to the bottom of what happened while he was away takes all his sleuthing skills, a little good luck, and a lot of time playing the planet's favorite sport, hussade. Things skipping along apace (too fast, in fact), Vance keeps the pedal pinned to the floor getting through the plot, leaving the reader wishing for a little more meat as the final pages turn.
Slowing things down a little and getting a little deeper into the story, the next Alastor novel, Marune, opens on a man Padero who is suffering severe amnesia. Apparently having had his mind wiped and then dumped on the fastest space ship off-planet, Padero must re-discover his origins and self piece by piece. A major piece revealed early, he finds himself headed to a baroque planet with a highly obtuse (read: Vance-ian) culture that requires severe parsing to understand who did him dirty. Padero's plight escalating wonderfully, Vance is on strong display in a manner reminiscent, at least partially, of Rhialto.
Saving the best for last, Wyst features an extreme version of bohemian communism that Vance uses to play off a free-market economy. Yes, Vance went political. (Don't worry, he does it fully in tune with himself and the values that have, to some degree or another, been present in his other stories.). A riot of neologisms that the reader can't help but crack up over, the story tells of an off-world artist named Jantiff who comes to the 'egalistic' society to learn and paint. He discovers something unlike he ever dreamed—even ending up applying to the connatic for assistance. Vance's sharp eye to human nature the guiding light of the story, indeed, the communist collective has some dark spots to address.
The three books do have common themes. The first would be the setting itself. While not what most would consider utopian, and I doubt Vance himself specifically framed the three novels as 'utopian', there nevertheless is a certain such vibe to the books. The leader of the trillions of people, for example, has time to play sleuth among the people's small affairs, rather than worry about wars, etc.
A second would be sexuality, or what passes for such with Vance. Typically conservative in his writings on sex, in these books Vance looks into the subject as much as he ever as. In Trullion, the preciousness of virginity/innocence, and the heights upon which it stands or falls, are discussed to a minor degree. In Marune, one of the major cultures does not copulate save blindly and wildly during one night of the month in which all hell breaks loose. In Wyst's bohemian communist paradise, sex is as casual as having a cigarette or coffee with someone, leading to some interesting thoughts on social interaction. And lastly, of course Vance being Vance, is the relationship between cultural phenomena and the spectrum between absurdity and sacredness said phenomena are regarded as, which, as always, makes for interesting commentary.
In the end, the spread of the Alastor trilogy is Jack Vance in a nutshell. Containing a variety of qualities and approaches to science fiction, from vengeance to whodunnit to social commentary, there is no repetition. As with the rest of Vance's oeuvre, however, there is likewise a spread of quality. The attributes improving with each novel, I wonder what Trullion, and to some degree Marune, would be like with the same focus as Wyst. While it was random that the Alastor trilogy ended up being the last virgin material of Vance's I read, I can now look forward to re-reading the best. Wyst, will certainly be on the list, and later Marune.