Fetching details from the dictionary...
to know thoroughly; to have full knowledge of
地元の道を知り尽くしている。
He knows every road in the area inside out.
彼はこの城の構造を知り尽くした。
He came to know the structure of this castle thoroughly.
師匠でもすべてを知り尽くすことはないだろう。
Even a master probably doesn't know everything there is to know.