User Story Mapping is a technique for organizing and prioritizing user stories. It addresses challenges with traditional backlogs by providing context and showing relationships between stories. The process shifts from requirements delivery to requirements discovery, recognizing that customers discover wants and developers discover solutions as things change. User story mapping decomposes user tasks into smaller tasks and organizes them into activities to form user stories. It is collaborative and fosters co-ownership by helping understand the user perspective and test for gaps by walking through the map.