wants to live; Svengaard suddenly finds that he does. He offers to care for the Durant's child, an offer Harvey accepts as he does not trust the cyborgs Boumard and Igan. The security forces of the Optimen surround the house and disarm (literally) Glisson. Ch. 18: The Tuyere debate what to do with the prisoners. They speculate that, if the infection of viability spreads, wiping out all the Folk and starting over is not out of the question. They decide to have the prisoners brought to themselves for interrogation. Ch. 19: A full assembly of Optimen meet in the Hall of Counsel. The prisoners are brought in, immobilized in a solid block. The Optimen begin to feel odd emotions, spiraling into greater and greater instability. Glisson asserts that reintroducing them to firsthand violence was a Cyborg ploy to destabilize the delicate equilibrium of the Optiman mind, and that the Cyborgs have won. A semi-hysterical Calapine converses with the prisoners, verging on killing them, but abruptly releases them instead. The Optimen descend into insanity; several, including Schruille, are killed in a stampede. The former prisoners try to help. Ch. 20: Calapine and the former prisoners discuss the new status quo. Glisson's gloating is cut off when a biological solution is proposed. Svengaard thinks that he will be able to stabilize the Optimen, and introduce the beneficial mutations of the Durant embryo on a wide scale, giving the Folk a lifespan of at least 12,000 to 15,000 years—longevity without the pernicious ossification of immortality. The novel concludes on a note of guarded optimism. Themes Continuing a theme present in many of Herbert's other works, the novel is principally concerned with the problems inherent in or caused by the inflexibility of a static system. The Durants find themselves a cog in the high-level machinations of competing factions, none of which have their own best interests at heart. A number of Herbert's other common themes pop up, including his interest in complex, rigidly codified or ritualized behaviors, reflected in the precise etiquette expected of those granted an audience with the Tuyere. Herbert's interest in exotic forms of communication takes the shape of the secret language of the Couriers, conveyed through subtle palm pressures during handholding. The longevity of the Optimen prefigures Leto II of the Dune saga. Reception David Pringle rated The Eyes of Heisenberg two stars out of four. Pringle described the book