noun
mastery
MAS-ter-ee/ˈmæstəri/
Thorough knowledge or skill in a subject or activity.
The gymnast's perfectly controlled position on the rings demonstrates mastery.

Etymology
Mastery first meant the condition of being a master: having control, dominance, or the upper hand. That command extended to intellectual command of a subject or art, hence complete knowledge or expert skill.
In context
this book displays that skill displays his mastery of the form of a novel the perspective change in the three different parts of the book
More examples
- Mastery of the basics makes advanced math easier.
- The pianist's mastery shows in every phrase.
- Achieving mastery takes more than memorizing a set of rules.
Forms
mastery
master noun — Someone highly skilled in a particular activity.
Similar words
- expertise
- Emphasizes specialized knowledge or experience in a particular field.
- proficiency
- Suggests competent performance without necessarily implying complete command.
- command
- Emphasizes confident use of knowledge, language, or techniques.