I do not understand the motivation that produced this book.
Reynolds is apparently known for hard sci-fi, but the premise of this book is so wild that I cannot assign this book to that genre, and its treatment of that premise seems scientifically dodgy. We're in a bleak world that's falling apart on the physical, technological, and social levels. As the story progresses, we trend ever downward. There seems to be no message and no aspiration here, unless you count "the world is shit and we don't have a choice except to live with it."
No character draws investment, because Quillon is missing most of his memories and has precious little depth, and the other characters are all traumatized and closed-off beyond our ability to ever know them. The book might have been setting up a sequel, but the author has stated a lack of intent to produce one.
It feels as if there's nothing in this beyond the author having an half-baked idea for a setting, and convincing a publisher to help him stretch it to the point of structural disintegration.
Contains spoilers
The ending to this really rang hollow.
Our villain, Victor, is an incredibly powerful psychic, someone with genetic abnormalities that would have killed him in the womb. He lived, because with his incredible psychic ability, he was able to force his mother's body to continue the pregnancy. After birth, he used psychic domination to coerce her into nurturing him, despite the cost to her (a homeless prostitute) and his hideous deformities. With today's eyes, we might immediately have concerns about the portrayal of the disabled, but it was written in the 1960s, so perhaps let's move on from that.
Victor has a plan to escape his crippled body by taking control of another psychic. Along the way, he drowns a man by taking control of his body and walking him into the ocean, and he sends a pair of psychic twins into a coma. Then, he takes an attempted suicide, a woman with psychic powers budding after that attempt, and dominates her into escaping a mental facility, erases some of her memories, implants a devotion to himself, and twists her memories of past acquaintances, before sending her back into the world some months later to fetch him a suitable host for his bid to transfer his mind. When she snares one, he drains the man to a husk, and very nearly succeeds in the attempt to transfer, except that the psychic twins have recovered and gained god-like powers and arrive on stage just in time to slap him on the wrist.
So, Victor has a bit of a rap sheet.
After his failed transfer, Victor lies dying—he was too busy with his gambit to maintain his psychic control over his malformed body, and his organs have failed entirely. In the same room is a psychic researcher, who, in a cruel twist of fate, is physically whole but is (unknowingly) psychically crippled. The twins, with the consent of both Victor and the researcher, help the two of them merge into two consciousnesses sharing the one intact body, with Victor's psychic power.
And everyone else accepts them.
That's the part that gets me. Yes, there's an understanding that Victor is motivated by bitterness and the cruel twist of fate that gave him such severe genetic flaws that he would not have even been born, if not for his psychic power. But nowhere is there an accounting for the terrible things he did, and attempted. Nowhere is there any mention of justice for the drowned man. He's just headmates with the researcher, respected and accepted into their new clique of psychics. And then... the pair of them choose to step back from that group, so that the researcher can make amends with his bitter, childish wife?
The setup was simply okay, the villain dated at best, and the character motivations in the last several pages are completely alien.
Just... don't. Read In Conquest Born, and see that the story is complete, and be happy with it. This sequel was written twenty years later and really, truly did not need to happen, and frankly detracts from the story.