This is the 3852nd most frequent Russian word.
автору
"To the author" (dative case of "автор").
Here, 'автору' is in the dative case, indicating the recipient of the action 'gave'.
Рецензент дал автору положительный отзыв.
The reviewer gave the author positive feedback.
'автору' is in the dative case, used after 'принадлежит' to indicate possession.
Книга принадлежит автору.
The book belongs to the author.
The word 'автору' is in the dative case here, showing the indirect object of the verb 'advised'.