I read a sci fi book a few years and I want to read it again, but cannot remember the titel. The story was(as I remember it)humans were battling an alien species in the center of the universe. Ftl was invented making "time travel" possible. One of the characters were arrested for something his older self did in the future. As I remember the book cover was white with a human face cathed in a greenish light.

I know.. not much to go on, but hopefully there is somebody out there with a better memory than me..

KAAN

"Forever War" by Joe Haldeman? Sequels are "Forever Free" and "Forever Peace".