This is a fascinating book with tremendous strengths and weaknesses. In a way, I wish that it had been written by Ballard or by Simmons who I think could have written it in such a way that it could have preserved the strengths and abandoned the weaknesses.
The book concerns Helward Mann a young man who grows up in the city of Earth. The city winches itself along tracks that it lays in front of itself and takes up behind. The city is in a never ending race to keep up with "the optimum" and travels at about a rate of a tenth of a mile a day. The city is moving across a landscape populated by barbarian tribes, that the city is forced to exploit these tribes to maintain its own existence.
The city itself exists in an inverted world, which is an infinite planet located in a finite universe. Consequently, the laws surrounding the city are different. To move forward, slows time and causes spatial distortions, to move backward is to slow time and cause the opposite spatial distortions. All of this is brilliantly executed. The world is bizarre and compelling. The strength of the book is in the descriptions of the mechanics of winching the city and in all the distortions that take place in relation to the city.
The inhabitants of the city believe themselves to be on another planet. It is very thoroughly telegraphed that they are in fact on a post-apocalyptic Earth and it is a weakness of the book that this is presented as a surprise. The other inhabitants of the Earth are clearly obeying normal laws of the Earth.
The end explanation of the world did not really make sense and I think that it would have been better to have no real explanation at all. I recently read The Crystal World by Ballard and there is not a lot of explanation for that world and that works better. The world is brilliant and the city being winched is similarly brilliant. Furthermore, while the main character is a bit flat, his progression as a person is very well done, as he becomes more conservative and unwilling to accept change or question his surroundings. That is very well done and sketching in the characters that appear and then disappear is also well done.
It confirms for me that the strongest tradition in SF is the British literary tradition. Overall, despite the fact that the writing is good and not great, the main character flat, the physical description too sparse and the end twist not very good. The strange world and winching city are so well done and the conservative reluctant exploiting society is very good as well. Overall a very good and under appreciated book.