This is the 988th most frequent Korean word.
대해서
"대해서" means "about" or "regarding."
In this sentence, '대해서' follows '그 문제에' to mean 'about that issue', indicating the topic being discussed or studied.
나는 그 문제에 대해서 더 알아보았다.
I learned more about that issue.
Here, '대해서' is used after '환경 보호에' to specify the subject of the discussion, which is 'about environmental protection'.
우리는 환경 보호에 대해서 이야기했다.
We talked about environmental protection.
In this instance, '대해서' is attached to '인권에' to indicate 'about human rights', detailing the book's theme or content focus.