"The Drowned World" by J.G. Ballard is a science fiction novel set in a post-apocalyptic world where rising temperatures have caused catastrophic floods and turned much of the planet into a sweltering, primordial jungle. The novel follows the story of Dr. Robert Kerans, a biologist who has remained behind in London to study the changes wrought by the rising temperatures. As he explores the flooded city, he encounters a group of survivors who have regressed into a primitive, almost tribal state. Along the way, he experiences vivid and unsettling hallucinations that seem to be a product of the extreme environment. As the novel progresses, Kerans is forced to confront the psychological and physical changes wrought by the new world, and to question his own sanity and sense of identity. "The Drowned World" is a powerful and evocative novel that explores themes of environmental collapse, evolution, and the dark recesses of the human psyche.