Moon of Three Rings
Krip, the Free Trader, is changed into an animal by the strange Moon Singer maiden in an effort to save him from the evil power seekers; but now he faces a more serious danger - that of not being able to return to his human form.
Andre Norton
Andre Alice Norton (1912-2005) was an American science fiction and fantasy author (with some works of historical fiction and contemporary fiction) under the noms de plume Andre Norton, Andrew North and Allen Weston. Norton published her first novel in 1934, and was the first woman to receive the Gandalf Grand Master Award from the World Science Fiction Society in 1977, and won the Damon Knight Memorial Grand Master Award from the Science Fiction and Fantasy Writers of America (SFWA) association in 1983.
Moonsinger
Moonsinger is also known as Moon Singer, Free Trader and Moon Magic.
Moonsinger consists of four primary books, and includes one additional book that complement the series but is not considered mandatory reads. The current recommended reading order for the series is provided below.