The Unconquerable — Keith Laumer

"DEFEAT" DOES NOT COMPUTE

The Unconquerable continues the Amplified History of the Bolo: From the earliest entries in the Bolo saga comes the account of a besieged American platoon and their experimental robot tank facing an enemy who controls a live volcano and inundates his opponents with molten lava. In the more distant future, Bolos must survive alien computer viruses infecting their electronic brains, repel attacks on their assigned planet by space pirates, outmaneuver alien battle machines with firepower and robot intelligence equal to their own, and challenge their own programming when that programming requires them to slaughter an enemy even though the war has ended. Throughout the galaxy, in the millennia to come, the formidable Bolos stand guard as the faithful and tireless protectors of the human race.