The Earth, it is dying—that pretty much sums up this sub-genre.
Low-moderate. Science and magic in Dying Earth are often indistinguishable. Indeed, in this sub-genre magic will often have justification, even in a weak science.
High. The end of times brings about reflection and creates potential for meaning. So while these stories are melancholy, they offer a greater depth of meaning to life.
High. Dying Earth stories have a tendency to focus on a lone survivor. With so much focus on single, or limited numbers of characters, they tend to be well developed with a strongly developed motivation.
High. A search for something, maybe resources or maybe hope, is often the driving force for a Dying Earth story. The searching is the plot. This is not to say that what is being sought will be found, but the search is important and integral to the plot.
Moderate-High. At the end of the world many humans resort to violence in order to survive. But sometimes, there is also love and compassion and hope (or at least a longing for hope)--so violence is not everything in the end.
By Jack Vance. A now classic novel about a distant future where the sun has become a red giant. Civilization lies in ruins and wizards fight. This series is the namesake of the sub-genre.
By Gardner Dozois and George R.R. Martin ed. Stories in Honor of Jack Vance. Some 22 authors contributed to this collection of stories and novellas, this collection takes place on Vance's Dying Earth.
By George R.R. Martin. On a world that is not Earth, but a world that is dying nonetheless, the protagonist must protect the woman he once loved. Secrets, bleakness, escape, revenge clash on this planet trapped in twilight.
By Robert R. McCammon. Earth is a wasteland of nuclear war. A malevolent force gathers followers to end a special child. This is the final battle between good and evil.
By Robert Charles Wilson. The stars go out—replaced by an alien-made barrier that slows the passage of time on Earth and the danger the sun poses comes ever closer.
By Gene Wolfe. An epic series set a million years in the future when the Sun has dimmed, the Earth has grown cooler and been transformed.
By William Hope Hodgson. A story of terror in which the cosmos themselves are perishing and the Earth is cast in eternal darkness.
By Ashton Smith. One of the sub-genre's first collections this sequences takes place on Earth's last continent in the far distant future.
By Philip José Farme. A story set so far into the future that the universe itself is collapsing on itself. An unlikely band of survivors (a man, his wife, a sentient rock, witches, slaves, thieves, plant-men) search for a way to another universe in order to escape
By Brian Aldiss. Earth has stopped turning and the moon is held in place by giant spiderwebs. A decidedly unique setting filled with imaginative and dangerous creatures and plants.