The back cover description is rather strangely constrained on my copy: It talks about a far flung galactic civilisation but it does not really mention any of the interesting features of said galaxy. In this future, space travel in actual 'star ships' has become rare. Instead, on settled planets - of which there are around a hundred - Earthmen use a 'go-board' thingie to travel from location to location. Brunner postulates that you pay to have a location memorised under hypnosis, you then punch the coordinates into the go board and emerge at your destination. We learn this through a character called Erik who is a freelance drug experimenter who has come to Yan.
The world of Yan, which is where the story is set, is quite fascinating. Brunner describes a world with aliens who are biologically very different from humans but physically resemble them in many ways of bilateral symmetry and he discusses the fact that while bilateral symmetry seems to be a bit of a rule in the known galaxy, finding a race as physically compatible with humans is uncommon. Psychologically, however, much less compatible. The Yan are believed to have had a larger, much more advanced, technological civilization at one time, as there are monuments scattered around the world, but by the time Earthmen arrived they had a smaller, incredibly socially stable and remarkably content society.
The Yan, for the most part are polite, hospitable and uninterested in human technology except for a small number of younger Yan who are fascinated by humans, mimic many elements of their culture and a couple have even entered into relationships with humans. Yes, there is sex with aliens, though it is not especially graphic.
The world is fascinating; some time in the past an exploding moon created a spectacular and unique ring in the sky, but for he planet it was a bot of a disaster and probably the end of the high civilization of the Yan. There is a very narrow band of liveable area on the planet with the equator and other regions being subject to huge numbers of meteorites and catastrophic disturbances. And everything is beautifully, lyrically decried in an intensely visual way that takes time to absorb and is delightful to read (if you are in the mood for this kind of book).
There is a significant, SIGNIFICANT quirk to the writing. There are many characters and points of view and the author skips from one to the other without even a paragraph break, no warning at all. He uses this technique to create a very rounded view of any scene and while I don't quite see how he does it, this tactic did not bother me at all. Normally I would not be crazy about this, but here I never really had any doubt as to which perspective I was seeing things from. It is really weird though. This is a really unusual reading experience in that sense.
Having set us up with the world and it's Earthmen inhabitants, we get a night when a huge moon rises in a sky that has not had a moon for decades. This moon is eventually revealed as the star-ship of Gregory Chant an interstellar 'artist' who creates world altering spectacles which include dramatizations of illusion in which the audience are actually participatory. He has been known as the most amazing artist ever, but also as someone who has shattered worlds and societies. So it is not with unbridled enthusiasm that everyone sees this 'the greatest artist of all time' arrive on the quite Yan. One of our protagonists is a poet, Marc Simon, who has gone native, lives with a Yan woman and specialises in translating Yan mythology and epic poetry. He is disturbed by Chant's arrival, but as an artist himself, gives him credit for inventing a whole new medium in which he is the unchallenged leader.
So from here on we have a pretty interesting story, with lots of different stakes, parts, intersecting plots and characters. I don't want to say too much about it, because this is totally a book that needs reading without too much bias.
However, after a while the different factions of human for or against a performance find they have no actual influence, when the YAN themselves ask Chant to perform. We eventually find that the real story Brunner is telling is about life, what an alien civilisation or consciousness could look like and it unfolds beautifully and unexpectedly and very believably.
Toward the end the Psychologist Dr Lem and the poet Marc, are in an observation dome together waiting for the performance to begin which may unleash/reprogram/heal the Yan into becoming all they can be and what they once were. That is what they talk about; civilisation and consciousness.
The ending is rather explosive,
This is a book one would have to be in a significantly specific mood to appreciate. It is not a fast read, because you have to be in a mood to immerse yourself in the descriptions. Without them, there is no level this book would work on that I can see because Brunner does an amazing job of unfolding the whole novel through dialogue, events and descriptions. It is a completely "show not tell" reading experience and I was really impressed and thoroughly enjoyed it.