This is the best book to learn about Docker from the scratch. Docker is the virtualization architecture from the future.
With Docker by Jordan Lioy, you will learn:
The basics - the theory behind Docker
Extensive coverage of Docker architecture
Deep-dive analysis of core concepts such as images and containers
Ways how Docker can organize your projects
Networking, volumes, and security
Docker certified associate (DCA) coverage
And much, much more!
It comes with a lot of examples to help you understand and implement every solution.