Forever peace - Joe Haldeman

In the year 2043, the Ngumi War rages. Limited nuclear strikes have been used on Atlanta and two enemy cities, but the war goes on, fought by 'soldierboys' -- indestructible war machines operated by remote control by soldiers hundreds of miles away.

Julian Class is one of these soldiers, and for him war is truly hell. The psychological strain of being jacked-in to his soldierboy -- and the genocidal results -- are becoming too much to bear. Now he and his companion, Dr Amelia Harding, have made a terrifying scientific discovery, which could literally take the universe back to square one. Except that for Julian, the discovery isn't so much terrifying as tempting....