This is the 9683rd most frequent Japanese word.
良雄
"良雄" is a Japanese male given name, typically meaning "good" (良) and "hero/man" (雄).
良雄 is a proper noun used as a person's name in this sentence, referring to an individual.
良雄は学校に行っています。
Yoshio is going to school.
良雄 is used as a possessive noun, indicating that the house belongs to Yoshio.
良雄の家は大きいです。
Yoshio's house is big.
良雄 is the subject performing an action, specifically writing the book, referenced in the sentence.