A Deepness in the Sky (Zones of Thought, #2)

Alternative Cover Edition can be found here. After thousands of years searching, humans stand on the verge of first contact with an alien race. Two human groups: the Qeng Ho, a culture of free traders, and the Emergents, a ruthless society based on the technological enslavement of minds. The group that opens trade with the aliens will reap unimaginable riches. But first, both groups must wait at the aliens' very doorstep for their strange star…