The avatar Hardcover – January 1, 1978 by Poul Anderson
 
In the immeasurable past a mysterious alien race known as The Others left mankind a challenging legacy, a 'gate' to the unexplored reaches of the stars. Humanity has utilized the gate to painstakingly colonize the Phoebus star system but has left the rest of the galaxy unexplored. In the midst of turbulent political upheaval on Earth, the exploratory ship Emissary leaves through the gate on a voyage of discovery. When the Emissary returns ahead of schedule the Social Welfare Party on Earth impounds the ship and imprisons its crew - and forbids all future space exploration. Dan Broderson, an entrepreneur and adventurer, commandeers a commercial spaceship from his own company and travels to Earth to find the Emissary. He locates the ship, confounds its captors and rescues some of the explorers, including the first alien to visit the solar system. But Broderson has to flee through the gate unprepared, to become a wanderer among the stars in search of The Others. They alone have the knowledge that will enable his ship to return home.
 
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