The War Between the Fifth Men and the Brain-Men was the destructive conflict in which the Fifth Men, having become independent of their creators, fought the Great Brains and the human automata. It ended with the extermination of the automata, the destruction or starvation of the Great Brains, and severe losses among the Fifth Men; civilization then fell back into barbarism and had to be rebuilt.

Origins and Division

The conflict followed the creation of a new population from a pair of individuals fostered by the Great Brains. The Fifth Men gradually asserted their independence and took control of their own destiny. Their creators, unable to understand or sympathize with the mentality of the beings they had made, tried to tyrannize over them. The struggle therefore grew from a rupture between creators and their creation: the Fifth Men’s emergence as an independent people met the Great Brains’ attempt to retain authority.

For a time, the planet was divided between two mutually intolerant communities. The account identifies the human automata as part of the eventual conflict and names the Great Brains and Fifth Men as its principal opposing populations, but it does not detail the political arrangements or specific incidents that divided them. The war is presented as the culmination of this prolonged division, not as a single isolated battle.

Course and Outcome

The narrative gives the war in compressed retrospect rather than describing its campaigns. It records a sweeping reversal of power: the human automata were exterminated, the Great Brains starved or were blown to pieces, and the Fifth Men themselves were decimated. The survivors’ losses were therefore not a clean victory. Even the population that remained in control of its destiny emerged reduced and faced the collapse of the society it had built.

The account supplies no battle chronology, named commanders, or explanation of how particular deaths occurred. Its emphasis falls instead on the conflict’s total consequences for the planet’s populations and civilization. The alternatives of starvation and destruction given for the Great Brains’ end preserve uncertainty about their precise fate, while making clear that their rule did not survive the struggle.

Aftermath and Historical Place

In the wake of the war, a dense fog of barbarism settled over the planet. The Fifth Men, like earlier human races after catastrophe, had to begin rebuilding civilization and culture from their foundations. The conflict thus interrupted their development rather than concluding it: the later account describes a mature Fifth Men society with extensive automation, abundant material power, and freedom from routine labor, but that achievement stands beyond the devastation and reconstruction summarized here.

Narrative Presentation and Significance

The narrator deliberately declines to recount the stages of the war in detail, moving from the Fifth Men’s creation and independence directly to the division, devastation, and rebuilding. This telescoped treatment makes the conflict a hinge in the long history of the species: the creators’ failure to understand their creation gives way to mutual intolerance, and victory leaves the surviving society facing a new beginning. The war’s significance lies not only in who survived, but in how thoroughly the struggle erased the conditions needed to sustain civilization.