This document discusses building multi-architecture Docker images using Docker's buildx tool. It begins by explaining the traditional way of building multi-arch images, which involves building separate images for each architecture and combining them with a manifest list. It then introduces buildx, which allows building targets for multiple architectures simultaneously during a single build command. Buildx relies on emulation to build images for non-native architectures. The document recommends using buildx to build everything as multi-platform and always using multi-stage Dockerfiles for builds. It concludes by providing some next steps for learning more about building multi-arch images.