It is an odyssey in which our male protagonist, Gren, takes a journey across a world, through unimagined dangers and impossible perils (while Lily-yo, our female protagonist, gets to journey up).

It is a tale of impossible wonders, part of a genre that, like The Odyssey, predates science fiction, its roots in the travelers’ tales of Sir John Mandeville and before, tall tales of distant places filled with unlikely creatures, of headless men with their faces in their chests and men like dogs and of a strange form of lamb that is actually a vegetable.

But above and behind all else, Hothouse is a novel of conceptual breakthrough—as explained by John Clute and Peter Nicholls in their Encyclopedia of Science Fiction, the moment of conceptual breakthrough occurs as the protagonist puts his head through the edge of the world to see the cogs and gears and engines turning behind the skies, and the protagonist and the reader begin to understand the previously hidden nature of reality. In Aldiss’s first science fiction novel, Non-Stop, the jungle is, as we will learn, inside a starship which has been traveling through space for many human generations—so long that the people on the ship have forgotten that they are on a ship. Hothouse is a novel of a different kind of conceptual breakthrough, for the various protagonists are more concerned with survival than they are with discovery, leaving the moments of “Aha!” for the reader to discover: the life cycle of the fly-men, the role of fungus in human evolution, the nature of the world—all these things we learn, and they change the nature of the way we see things.

Hothouse is plotted by place and by event and, over and over, by wonder. It is not a novel of character: the characters exist at arm’s length from us, and Aldiss intentionally and repeatedly alienates us from them—even Gren, the nearest thing we have to a sympathetic protagonist, gains knowledge from the morel and becomes estranged from us, forcing us from his point of view into his (for want of a better word) mate Yattmur’s. We sympathize with the final humans in their jungle, but they are not us.

There are those who accuse science fiction of favoring idea over characters; Aldiss has proved himself over and over a writer who understands and creates fine and sympathetic characters, both in his genre and in his mainstream work, and yet I think it would be a fair accusation to make about Hothouse. Someone who made it would, of course, miss the point, much as someone accusing a Beatles song of being three minutes long and repeating itself in the choruses might have missed the point: Hothouse is a cavalcade of wonders and a meditation on the cycle of life, in which individual lives are unimportant, in which a nice distinction between animal and vegetable is unimportant, in which the solar system itself is unimportant, and in the end, all that truly matters is life, arriving here from space as fine particles, and now passing back on again, into the void.