The suffix -phile is used for making nouns and adejctives that describe a person who loves or likes something a lot. In other words, it means someone who likes or enjoys certain things.
In this case, the root word is biblio which means book.
Whe the root word and the suffix are combined, biblio + phile, it forms a new word which is used to refer to a person who loves books. It also refers to that person that collects them.