The Ship Who Saved the Worlds by Anne McCaffrey, Jody Lynn Nye
Two complete novels in one huge volume: The Ship Who Won: Like Helva, the Ship Who Sang, Carialle was born severely physically disadvantaged; and like Helva, Carialle decided she would strap on a spaceship. Her brawn is a guy named Keff. Searching the galaxy for intelligent beings, they found fuzzy little aliens, polite and eager to please. Unfortunately, they were slaves to a race of sorcerers, who possess powers of frightening potency, and who were neither polite nor the least bit eager to please.
The Ship Errant: Carialle and Keff had succeeded in liberating the ""globe-frogs"" from their servitude to dictatorial humans, but now they must return them from whence they came. And to get there, they must transit a sector where Carialle was stopped and boarded, experiencing a trauma so intense it nearly destroyed her mind. And it's beginning to look as if the beings who caused this are the very globe-frogs they have just made friends with. . . .
At the publisher's request, this title is sold without DRM (Digital Rights Management).