Andre Norton and Dorothy Madlee's beloved series for young readers: Star Ka'at
Two intelligent, talking Ka’ats from a super-race come to earth on a strange mission. In ancient days, Ka’ats had visited Earth and some had stayed to live in peace with humans. Then the humans cruelly turned against their friends. Now Ka’ats from outer space have come back to try to rescue their cat kin.
Although the Ka’ats believe that humans are inferior, warlike beings, they form a deep attachment to two young orphans, Jim and Elly Mae. Their relationship plunges Jim and Elly Mae right into the middle of the Ka’ats' dangerous rescue mission on Earth!