Animals, reptiles, fishes, insects—most such species have retreated from their ecological niches, going extinct and being replaced by semi-sentient vegetable equivalents, evolved from the plants that thrive in the hothouse environment. The "traversers" who webbed the Earth and Moon together are mobile and autonomous plants. So are the thousands of vicious predators who inhabit the single continent-wide banyan tree which is the jungle home to humans, one of the few remaining species of animals on the hothouse Earth.

Humans are now one-fifth the size of yore, and green-skinned. They exist in small packs in the middle canopy, barely avoiding death from above and below. Their minds are sluggish, their rituals primitive, their culture minimal, their memories short.

Our focus is one such group led by Lily-yo, a wise female. She and her elderly peers are preparing to make a traditional transition to the Moon by hitching a spider-ride. They regard the lunar voyage as an excursion to the afterlife, but in reality they will mutate into "flymen," the next stage of human life. The elders leave behind a youthful cadre, led by a woman named Toy. Toy's main rival for power is a young man named Gren, our ultimate protagonist.

After inadvertant adventures by the savage sea, Gren and a woman named Poyly becomes separated from their tribe. They are colonized by the symbiotic morel fungus, which adds to their intelligence but also drives them cruelly on its own errands. They encounter a tribe of herdsmen, and make friends with a woman named Yattmur. When Poyly dies, Yattmur becomes Gren's mate.

Becoming lost at sea with some subservient subhumans named tummy-belly men, the pair experience a variety of trials, on an island, a glacier and the mainland, which ultimately bring them to the twilight realm and its own brand of strange creatures. Ultimately, a reunion there with Lily-yo reveals the final fate of humanity.

A fantasia of nature and devolution

The Dying Earth was never more alive than in Aldiss's baroque, poetic extravaganza. Like some merciless Darwinian exegesis, this novel brutally rips aside the veneer of mankind's assumed special place in the universe, and casts our species as just another desperate survivor amid titanic forces. As such a novel, it combines two subgenres: the Dying Earth and the Men in the Walls schools.

The first mode is well-known, arising perhaps with Wells' apocalyptic visions in The Time Machine (1895) but certainly being fully codified with Hodgson's The Night Land (1912). And, of course, by Jack Vance's seminal book that lent the subgenre its name (1950). Aldiss takes the category to extremes by destroying all continuity with the past. There are no museums of ancient history or time-worn castles here. Merely a vegetable world that has grown over all the bones of civilization.

As for the other element, the Men in the Walls motif, that crystallized most clearly with the William Tenn novella of the same name (1963), wherein mankind was reduced to a rodent-like existence. Aldiss might have been inspired also by the savagery of Harry Harrison's Deathworld (1960) And later on, Thomas Disch was surely working consciously in this vein when he produced his novel The Genocides (1965) shortly after Aldiss.

Combining these two concepts—Dying Earth and Men in the Walls—was a stroke of genius. But the real brilliance resides in Aldiss' gorgeous, vivid, tactile prose. The hothouse world becomes as tangible as our own with descriptions like this: "The bird ... was headless. Slung between the stiffly extended wings was a heavy bag of a body, peppered with the corneal protuberances of its eyes and its bud corms; among these latter hung the pouch from which its tongue now extended."

With endless such flights of extravagant fancy, including a Seussian terminology for the strange animals, Aldiss produces the ultimate SF kick: cognitive estrangement. But he does not neglect the human verities of love, pride, courage and fear. Gren and Yattmur could be 20th-century souls caught up in a world war that never ends.

Aldiss would not work in this magnificent world-building mode again until the Helliconia Trilogy (1982-85), where he would almost, but not quite, surpass this early milestone.