"The Lost World" is a novel written by Sir Arthur Conan Doyle, the British author best known for creating the iconic detective Sherlock Holmes. Published in 1912, this adventure novel stands apart from Doyle's more famous detective fiction and is known for its exploration of the unknown and its contribution to the "lost world" literary genre.

The story is centered around the character of Professor Challenger, an eccentric and larger-than-life scientist who, like Sherlock Holmes, became one of Conan Doyle's memorable literary creations. Professor Challenger claims to have discovered evidence of prehistoric life in the Amazon rainforest and invites a group of individuals, including the narrator Edward Malone, to join him on an expedition to verify his findings.

The group embarks on a perilous journey into the uncharted and remote plateau in South America, where they encounter a world seemingly frozen in time. Dinosaurs and other prehistoric creatures roam the plateau, and the explorers must navigate not only the dangers of the natural world but also the challenges of their own personalities and relationships.

"The Lost World" is a pioneering work in the "lost world" subgenre of adventure fiction, which involves the discovery of isolated and prehistoric environments that time forgot. It predates other famous works in this genre, such as Edgar Rice Burroughs' "The Land That Time Forgot" and Sir Arthur Conan Doyle's contemporary H.G. Wells' "The Time Machine."

The novel combines elements of science fiction, adventure, and exploration with themes of human curiosity, bravery, and the clash between the modern world and the primeval past. It also touches on the ethical implications of encountering and documenting creatures thought to be extinct.