The birthday of the world - Ursula K. LeGuin

'Her most important book since ALWAYS COMING HOME and her most satisfactory collection since her first, the brilliant, THE WIND'S TWELVE QUARTERS. A formidable and rewarding work, a prime candidate for best SF collection of the year. An essential book.' LOCUS
Six of the eight piece are set in Le Guin's classic Hainish cycle. The title story, 'The Birthday of the World', stands alone and the final piece, 'Paradises Lost', is a new short novel original to the collection, a major addition to the generation starship subgenre of science fiction.