(The first book in the Saga of Cuckoo series)
A novel by Frederik Pohl and Jack Williamson
Essef - Cockoo was coming. No one knew what it was, but everyone knew it was trouble. Designated Object Lambda when it first appeared on the fringes of the galaxy, 20,000 light-years away, it was travelling at one sixth of the light speed. An existing space probe was reoriented to intercept, and staffed with replicates of both humans and aliens. Then the space probe began to leak radiation...
Used availability for Jack Williamson's Farthest Star
January 1983 : USA Mass Market Paperback
February 1976 : UK Paperback
January 1975 : USA Mass Market Paperback