Following the model of:
Provide QUALITY books and their approximate skill level in your answer. Add a short blurb/description about each book that you have personally read/benefited from. Books that meet the criteria will be added to the official community wiki answer.
Preferably, only outstandingly good books on Python 2 should be included as Python 3 is the future.
A tag search for "Python" and "Books" returns no complete book list results as of writing this question.