Rax

Set on a planet whose elliptical orbit creates intense summers and long, cold winters, it tells of the love between Drove and the girl Pallahaxi-Browneyes, whose affair is set against civil war and the dread approach of winter. It's also a brilliant depiction of an alien world, with bizarre tidal effects and even stranger native creatures. This is a love story, and a science-fiction story, and more besides. It's also a beautifully-written, lyrical adventure story with one of the finest closing lines in the genre.