Rainforest is a 1987 novel by Jenny Diski about a young female English academic whose ambitions are to lead a sane and sensible life and to contribute to humankind's understanding of the natural world but who eventually has a mental breakdown when faced with too many people surrounding her who, driven by desire and lust, behave irrationally, indifferently, and irresponsibly towards her, each other, society, and the planet.

She visits her widowed mother in the country every once in a while and spends pleasant weekends with her, has a satisfactory relationship with her boyfriend Luke, a biochemist, and has started making plans for, and is very much looking forward to, her research project which will take her to an isolated spot in the tropical rainforest that covers large parts of the island of Borneo.

When, shortly before her departure, she meets Joe Yates, who has been hired as her replacement for the six-month period she will be gone, Mo is both appalled and attracted by his directness but rejects his overt sexual advances as well as his fatalistic philosophy of life.

In Borneo, she behaves very professionally, fervently believing that through her academic work she will increase the sum total of human knowledge about the tropical rainforest.

Questioning the validity and relevance of her findings, he eventually succeeds in seducing her—they have wild, unbridled sex in the wilderness—only to tell her afterwards that he is only passing through and his current girlfriend, one of his students, is actually waiting for him in the nearest town.