With this is bound (inverted) as issued: Chandler, Arthur Bertram. Space mercenaries. New York [c1965].
Summary
Space mercenaries: The former Empress of Outer Space becomes a mercenary for the Galactic League of the abolition of suppression and slavery.
The caves of Mars: Ric Colter lost is arm in an interplanetary exploration. Thanks to Martian panacea he could grow his arm back, but complications arise when he goes to one of the colonies where it is administered.