Docker allows users to package applications and dependencies into standardized units called containers. Containers provide isolation and portability benefits similar to virtual machines but with less overhead. Docker uses resource isolation features of the Linux kernel to run multiple containers simultaneously on a single host. Common uses of Docker include accelerating developer onboarding by providing consistent environments, enabling continuous integration workflows, and easily deploying applications across different computing platforms like physical, virtualized, and cloud environments. Hands-on examples demonstrate how to build Docker images from Dockerfiles, run containers using the Docker CLI or Kitematic GUI, and explore common Docker commands.