The major topic of the book All You Can Ever Know by Nicole Chung is racial identity and belongingness.
The major topic of a book refers to the central theme or idea that connects the parts of the story together. It is like the main pillar of a building.
Each book written has a main theme or central idea with other supporting themes.
Thus, we can conclude that Nicole Chung's All You Can Ever Know concentrates on the theme or topic of helping the readers to discover their racial identity and belongingness.