This book is one of my all time favorites. First of all, UKL is an amazing writer. The book plays with the nature of reality and idea of creative dreaming. I believe UKL studied Australian aboriginal cultures' understanding of the dreamtime and how it interacts with the worldtime, and that study informs this book, as well as her book "The Word for World is Forest". The book is wildly creative and touches on elements of the human psyche that are far beneath the surface. The ideas she explores just feel RIGHT on some deep level.
Her writing is marvelous, too. UKL is the master of saying things without saying them. Listen carefully to her words. They're quite poetic. Example: one of the aliens refers to our hero George Orr as Jorjor, and it takes a second for George to recognize his name in that "barsoomian bisyllable". Perfect phrase! :)