"Non-stop" is a classic of science fiction, and stands the test of time amazingly well. Like "Learning the World" by Ken MacLeod, "Non-stop" deals with a massive ship (and self-sustaining ecosystem) traveling between stars over the course of generations. Unlike "Learning the World", the society of the ship that is the focus of "Non-stop" has broken down in a fundamental way, devolving in some ways, evolving in others.
One thing that makes this book remarkable is how wonderfully constructed the narrative is. The origins of society and of the inhabitants themselves are revealed in a way that keeps the reader engrossed. The plot twists, and there are many, all emerge naturally, and hold up to close scrutiny when rereading the book. None of the twists or revelations seem cheap or contrived, which is refreshing if you've seen one too many Hollywood blockbusters or episodic TV series (I love "Heroes" and all, but seriously, the strain of having to come up with the next plot twist that fits the prior narrative must be just exhausting).
Another thing that amazed me when leafing back through the book was just how short each seminal section of the book turned out to be. The major revelations seldom take more than a few paragraphs. It's as thought the economy of a brilliant short story author (Borges, for example) were turned towards creating a novel as a series of linear vignettes. I'd imagine the work would have worked well serialized, and I'm sure it also will fit the attention span of the traveling reader as well.
At any rate, the book is a quick read (and reread), and is highly recommended. I look forward to picking up Aldiss's history of Science Fiction as well as further of his fiction works in the future.