Though its title is similar to The Forever War and both novels deal with soldiers in the future, Forever Peace is not a direct sequel, and takes place on Earth much closer to the present day. Also, instead of extraterrestrials, the main character and his fellow soldiers are fighting third world guerrillas in an endless series of economy-driven wars. Rather than fighting in person, the American troops use remotely controlled robots (called "soldierboys") which are nearly invincible. Only the nations that possess molecular nanotechnology are able to build such machines. These nations form the first world. The necessary nanotechnology is called the Nanoforge, and can produce anything from raw atomic materials.