Le Guin's Hainish series begins with the assumption that centuries ago humanoids from the planet Hain ventured through the solar system establishing colonies on various planets including Earth. For mysterious reasons these colonies lose all contact and knowledge of each other until the 21st century when an attempt is made to establish a galactic league. Individual stories in this loosely organized series explore the inherent communication difficulties...

"Somewhat sentient, the omega clouds obliterate life on every planet in their path. Now one of them is predicted to reach Earth in about 900 years. But between Earth and the cloud, lies the home world of the Korbikkan race. They are humanoid sentients and one of three sentient races known to humanity. Now, mankind must decide whether to marshall the science resources needed and to bring to bear the weaponry needed to save another race without putting...