ISBN 0-553-29921-2 (US pbk)

"It is the twenty-first century. Earth's space program is thriving, with a colony in place on the Moon. And then an incredible discovery is made on the lunar farside. A massive structure is being erected by living machines -- microscopically small, intelligent, unstoppable, consuming whatever they touch. All who come near them die horribly. Meanwhile, the mysterious structure continues to grow, expand, take shape. And its creators begin to multiply...
"Is this the first strike in an alien invasion from the stars? Or has human nanotech experimentation gone awry, triggering a lon-predicted disaster? As riots rage across a panicked Earth, scientists on Earth and on the Moon race to learn the truth before humanity's home is engulfed by the voracious machines and its inhabitants perish in the most terrifying plague ever known." [jacket blurb, US pbk, 1993]

"Anderson and Beason are at the top of the class of the new generation of hard-SF writers." --Jerry Pournelle.