Conqueror's Legacy by Timothy Zahn (The Conquerors Saga #3)
HARDCOVER BOOK CLUB EDITION  BANTAM BOOKS
Book and dust jacket are like new.
While humans and alien Zhirrzh prepare for galactic war, a handful of individuals from both sides learn that the reason was all a misunderstanding. Both were mistaken. To avoid extinction for both their races, this band becomes the focus of a subtle dangerous force that intends overall destruction.