Docker Fundamentals is a practice-first course for engineers who need containers to work, not just to sound familiar. You start with why containers exist at all — dependency conflicts, environment drift, the "works on my machine" handoff — then move into the mechanics: how image layers and the build cache really behave, what COPY does that ADD doesn't, why ENTRYPOINT and CMD interact the way they do, and why your container ignores SIGTERM. From there you cover the parts people get wrong in production: named volumes versus bind mounts, mount shadowing, publishing ports versus talking over an internal network, embedded DNS on a user-defined bridge, secrets that survive in image layers, and running as a non-root user with a read-only root filesystem. You will slim images with multi-stage builds and distroless bases, push to a registry with digest pinning and vulnerability scanning, wire up multi-container apps with Compose, and diagnose the failures every Docker user meets — a container that exits immediately, exit code 137, "port is already allocated", "no space left on device", and permission denied on a mounted volume. Every topic is drilled with scenario questions rather than definitions, so you finish able to read a Dockerfile, predict what it builds, and fix it when it breaks. This is course one of the Docker & Kubernetes Mastery series; orchestration is covered in the Kubernetes courses that follow.