Exultant
by Stephen Baxter

Description:
Twenty-five thousand years have worn away. Mankind has become a mighty star-spanning host, and is locked in a millennial war for the Galaxy itself. A war against the utterly unknowable Xeelee." "We have survived the shock of alien occupation and for twenty millennia now humanity's fight for survival has been led by the 'Coalition'. You are expected to live bravely and die young - and only successful soldiers pass on their genes. It has been an immense selective-breeding programme; in this age, the superior form of human is a child soldier. And it has been successful; the 'Third Expansion' of mankind has swept us across the Galaxy - but it has stalled at the Galaxy centre, where the Xeelee have their fortress. And the Xeelee have survived many cosmic transitions; they aren't going away.