01 - Citadel of Lost Ships by Leigh Douglass Brackett

In a world where space debris forms a Gypsy society, the last free races of the Solar System navigate a labyrinth of danger and intrigue. Roy Campbell, a hunted outcast of the Coalition, ventures into this treacherous realm seeking refuge for the Kraylens of Venus. However, he soon discovers that this sanctuary has transformed into a perilous slave trap, from which escape seems impossible.