As the "spotlight reviews" state, this is one of Silverberg's best, and handled in an unusual and engaging plot style.
Silverberg has invented a future "utopian" society where the earth supports 75 billion people "comfortably" in terms of physical resources -- and the society sees expanding that population rapidly as its main reason for existing. A clever balance of technology, energy efficiency, and agricultural balance all makes this seem possible.
What is so great about this to me is how Silverberg gradually brings to light the true horror of living in this society, by having us share the thoughts and experiences of a series of its members as the novel progresses.
In each case you see that on the surface, all seems well, yet ALL of these people are terribly unhappy and have no true sense of purpose or connectedness.
Why? Well, handling the population has required huge sacrifices. Absolute conformation to the norms is an absolute requirement. Failure to adhere to such norms is met with brainwashing, or for more aggregious cases (or where the brainwashing fails) summary execution by being dumped into the nearest matter-to-energy converter -- where your atoms "serve" society without causing any pollution. There is still a heavy class structure to society, with all the ill emotional effects that holds today, and the lucky few chosen for the top reap all the benefits -- NOT for the good of themselves more than for "the people".
The results, which Silverberg gradually makes us realize is a society which: allows no personal property, pays virtually no attention to the emotional needs of its children, demands total conformity and obedience upon pain of death or being stripped of all personality, gives no choice over where or how one lives, gives no choice over career, interests, mates, and has most of its members taking hallucinogens as a socially accepted psychological crutch. Also, religion is a pre-packaged standardized psychological crutch, thrust on anyone feeling unhappy with essentially the "you have to have faith" mantra. Finally, nearly everyone feels like a failure for not LIKING their role in the SHAM that society is full of happy members.
Now, about 30 years after this novel was written when we look around at the first world -- the parallels are eerie. As the global population continues to mount rapidly and our technologies allow us to live more and more in isolated boxes and consume prepackaged "goods" in ever more standardized forms by our leaders, our media, our corporations, our religions, and our own wants -- one has to wonder if Silverberg was forecasting the inevitable psychological state of man, or if he just got lucky.
Either way, the result was brilliantly insightful. This book is easily a peer to such classics as "Brave New World", "1984", and "Animal Farm" in terms of the clarity of its vision.