This is the 7647th most frequent Japanese word.
勝郎
"勝郎" is a Japanese male given name, typically meaning "victorious son" or "winning son."
In this context, '勝郎' is used as a proper noun indicating the personal name of an individual, followed by the honorific 'さん'.
勝郎さんは毎朝ジョギングをしています。
Katsurō jogs every morning.
Here, '勝郎' signifies the creator or author of the book, and the phrase 'によって' specifies that he is the acting agent.
この本は勝郎によって書かれました。
This book was written by Katsurō.
In this sentence, '勝郎' indicates the subject who achieved victory, which aligns with the similar meaning of '勝' as in 'winning'.