In Gunn's 22nd century, memory has been reduced to its chemical constituents; vicarious experiences are available as protein extracts in pill form; and so the populace is split between creative Dreamers (who produce the pills), sybaritic pill-popping Poppets, a small band of old-fashioned worker ""Volunteers"" (doctors, historians, etc.), and the handful of critical, progressive Synthesists at the self-sufficient urban center run by the Mnemonist (""M""). Cyborg M is dying, however, and must choose his successor. So, using memory proteins and computerized senses, he observes a series of candidates among the Dreamers, Volunteers, and Synthesists--all of whom more or less withdraw into capsule-inspired dreams. That's the fillip of plot here, and Gunn (The Immortals, Kampus) weighs it down with literary allusions, some gratuitously nasty sadism, drippy love stories (involving the candidates), chunks of warmed-over Greek mythology, and much tired philosophizing: ""questions still pounded against the inside of his skull, but now they were tinged with statement."" A few intriguing ideas--but mostly familiar ""heavy"" sf preoccupations in a labored, listless treatment.