Decision at Doona (Doona Series #1)

After the first human contact with the Siwannese ended in a mass suicide, the Terran government made a law that no further contact with sentient aliens would be allowed. But since their own planet was overcrowed, they looked to colonize Doona—until they found the Hrubbans. Their choice was simple but dangerous. They could kill the cat-like Hrubbans, or for the first time in history, learn to to coexist with an alien race....