Mannie is a fictional character from the novel "The Moon is a Harsh Mistress" by Robert A. Heinlein. He serves as the narrator and is a computer technician on the lunar colony. Mannie is known for his intelligence, resourcefulness, and strong sense of justice, which drives him to become involved in a revolutionary movement against the oppressive Earth government. Throughout the story, Mannie collaborates with other key characters, including Luna, a self-aware computer, and Wyoh, a passionate activist. Together, they work to inspire the lunar inhabitants to fight for their freedom and independence. Mannie's journey highlights themes of liberty, technology, and the struggle for self-determination.