Coyote Horizon — Allen Steele

The planet of Coyote has become the last, best hope of humankind, but it has also become the principal point of contact with the hjadd, the alien race encountered by a European starship many years earlier. Although the hjadd have built an embassy near the original colony, they remain a mystery.

And as the colonists make preparations to explore the rest of the new world, ex-convict Hawk Thompson discovers more about the hjadd than anyone has learned before--and his knowledge will change human history?