"The Lost Steps" is a novel by André Gide, published in 1925. It follows the journey of a composer named Marco who embarks on an expedition into the South American jungle in search of a primitive society. As he travels deeper into the wilderness, he grapples with existential questions about civilization, art, and the meaning of life. Throughout his journey, Marco encounters various characters, including the Indian and the explorer, who challenge his views on modernity and authenticity. The novel explores themes of isolation, the conflict between civilization and nature, and the quest for self-discovery in a rapidly changing world.