"Five of our worlds are missing". That was the essence of the report that shocked the galactic Nomads at their annual meeting. For each of the mighty star-ships reported vanished was a world of its own - a man-made, self-sustaining city-state housing thousands of people. The Nomads themselves were an unplanned by-product of man's conquest of the stars. They were the gypsies of the distant future, the restless rovers of outer space. But to Joachim of the peregrine tey represented a way of life that was to be dearly defended. So it fell to him to make his own world-ship the bait in a cosmic trap set to catch the galaxy's unknown foemen!
Poul Anderson (1926-2001) was born in Pennsylvania of Scandinavian stock. He started publishing science fiction in 1947 and became one the great figures in the genre, serving as President of the Science Fiction Writers of America, winning multiple Hugo and Nebula awards, and was named a SFWA Grand Master. He collaborated regularly with wife, Karen, and their daughter is married to noted SF writer Greg Bear. Poul Anderson died in July 2001.