Review
Environmental degradation and over-consumption are destroying Bel'lar's home world. A growing movement among the people is to adopt the Syn (synthetic) lifestyle, to practically live on synthetic chemicals. The minority Organs (organic) want Bel'lar to take a ship called Light Traveler, and a small crew, to the semi-mythical blue/white planet, to see if it is suitable for colonization.
Just before their hurried departure, just missing a mob of rampaging Syns, a beautiful mystic and seer named Ry Sing gives Bel'lar a horrifying vision. Long, long ago, Bel'lar was the Great One, the religious leader on a world called the Planet of Abundance. It faced a similar over-consumption crisis. His advisers convinced him the purifying the planet was the only option. It wasn't until it was too late that Bel'lar realized that "purifying" the planet involved using several nuclear weapons buried around the planet to kill everyone. Even worse, scripture says that he is destined to do it again.
After visiting the blue/white planet, with an unscheduled stop at its smaller, red, dead planetary neighbor (the Planet of Abundance), Bel'lar and crew head home to tell the people what they have found. Because of time dilation, nearly 350 years have passed since they left. Their world is on the verge of environmental collapse. The air and water are full of synthetic chemicals. There are no fish or animals left. Genetic modifications from the Syn lifestyle have made the population fat, hairless and stupid. The few Organs who are left are forbidden to leave their compound on pain of immediate death by the Syns.
An entire religion grew up around Bel'lar during his absence. A competing religion has grown up around a man named Quasar, leader of the Organs, and de facto ruler of the world. Bel'lar is to be forced to publicly recant (he has no interest in being another Great One), so that the people will have no choice but to worship Quasar. A short distance away is another planetary purification device. Does Bel'lar "purify" another planet? Is there anyone worth saving?
Personally, the first half of the book, when the crew visited the two planets, felt a little too new age-ish. The second half of the story, when they were back home, was much better. It will give the reader a lot to think about, and it is still worth reading.