If you ever saw the movie Inception, I really do not need to describe the book to you; all of the major ideas of the movie came straight out of this book. Anyhow, Charles Render is a Shaper, in other words he is a psychiatrist who treats people by entering their dreams and changing them for the benefit of the patients. When a woman asks him to help her become a Shaper he is sure it is completely impossible in her case as she is blind from birth. He is still interested enough to try. In fact he is so interested he forgets that the altered dream can affect the Shaper in charge as well.
Zelazny is the master of prose which is clearly shown by this novel yet again. The ideas were novel at the time of writing, if somebody else wrote something similar before I am not aware of it. He also managed to pack a lot of ideas into a very limited space: my copy has a little over 100 pages. I have to repeat here what another reviewer said about the novel: while almost everything is good, the execution lacks; I could not say it better myself. On the whole the novel is underwhelming. It is not bad by any stretch of imagination, but it is most definitely not among Zelazny's best. I am a fan of Zelazny, so the ration would be 3.5 stars - a little inflated, so I will round it down.
This review is a copy/paste of my LeafMarks one: https://www.leafmarks.com/lm/#/users/10968/books/14926/review