
My favourite collection is "The Birthday of the World", especially the stories "Solitude" and "Paradises Lost". (Maybe skip "Old Music and the Slave Women". It builds on other books and is incomprehensible without them; or at least it was to me.)
For a shorter story (~50 pages), I'd highly recommend Paradises Lost by her. Many people have written stories about generation ships, but this one is absolutely stunning and truly marvelous.
