This book won the Nebula and Hugo awards for best novel in 1998. That's quite an impressive accomplishment.
Joe Haldeman was already a well-known figure in science fiction publishing, mainly for having published "The Forever War" in 1974, which also won the Nebula award in 1975 and the Hugo award in 1976. Despite what you might think from the title, though, "Forever Peace" is not a direct sequel to "The Forever War." It does, however, explore issues about war and its effects on soldiers from a different perspective.
In "Forever Peace," Julian Class is one of a group of soldiers who fight by operating "soldierboys." These are remote controlled battle machines, which allow the war to be fought by soldiers who remain safely in their homeland, hundreds of miles away from where the action is taking place.
The nanotechnology and other advances that make this possible are, however, not shared by everyone. Some countries have it, and fight against less technologically advanced nations whose people have to confront the soldierboys the old fashioned way, and fight and die themselves.
The soldiers who use the soldierboys are able to see what's happening during a battle as if they were really there, and the experiences they go through can still take an emotional toll. These experiences also tend to make soldiers bond closely between themselves, in a way that civilians can't understand.
War is also depicted as a form of entertainment. Video taken from battles is distributed for people's viewing pleasure. Some groups of soldiers even have fans who closely follow all of their battles.
In order to be able to connect to a soldierboy and work with a squad of soldiers, each individual soldier has to undergo an operation on their brain so they can "jack in." The procedure doesn't always work, though, with potentially serious consequences if it goes wrong.
(I'm going to re-iterate my spoiler warning here).
This technology, which enables one to jack in, turns out to have an ironic effect. Julian and some of his friends discover that, while it allows soldiers to communicate and literally be inside each other's heads, prolonged exposure to this linking with others can permanently make one more empathetic. And that could make it harder for a person to harm another human being. That makes them realize they may have found a tool that could bring about peace and end war at last.
That makes it a good example of a theme that runs through much of the science fiction genre. A lot ot scientific discoveries and technological innovations aren't necessarily good or evil all by themselves, but how human beings choose to use them is always the vital question.
There's another, parallel plot involving some physics experiments and an attempt to re-create the big bang, but which might have hugely destructive consequences. This threat adds more ugency to the characters' quest to change the world.
Many of the issues Haldeman brings in to this story are very real and relevant today, even though this novel is set in the future. It's a nice example of the way science fiction can show what can happen if we continue on the course we're on. The stark difference between have and have-not nations, highlighted by the way wars are fought is one example. War as a form of entertainment is something all too true - how many people are glued to their T.V. sets when a war is on? It's been that way since the Vietnam war, hasn't it? And the fact is, there is technology available today that is coming closer to making remote control war possible. Or even beyond that, automated war - there have been stories in the news recently about the use of armed robot drones in Iraq.
That's the sign of a good novel - no matter where or when it takes place, it shows us something relevant to the world today.