Wall Around a Star

"Wall Around A Star" is the second book of the "Saga of Cuckoo" series, the first of which was "Farthest Star". The author is Frederik Pohl, in collaboration with Jack Williamson. The cover art for the 1983 edition was done by David Mattingly. [http://www.iblist.com/book19581.htm]

Cover Blurb

Butterflylike aliens had brought Earth into the galactic culture, but she was a poor relation, valued only for the living human bodies she rented out for whatever purpose her nonhuman customers desired. Then Cuckoo was discovered. Millions of miles in diameter, less dense than air, it had a solid surface that was home to many races — including a species of Man. And that was odd, for Cuckoo was from another galaxy! Suddenly, one human, a linguist, became very important. If Jen Babylon could solve the mystery of Cuckoo's records he might raise humanity's standing among the older races —and he might also save the galaxy!

* Publisher. Del Rey Books (January 12, 1983), ISBN 0-345-28995-1.