This is the 7106th most frequent Polish word.
im
"Im" means "them" (dative case) in English.
In this sentence, 'im' is functioning as the dative form of 'oni' (they), indicating to whom the book should be given.
Daj im książkę.
Give them the book.
Here, 'im' also serves as the dative form of 'oni,' showing to whom the concern about success applies.
Zależy im na sukcesie.
They care about success.
In this sentence, 'im' once again acts as the dative form of 'oni,' indicating to whom the way was shown.