The Great Wizard of the Library is a Manga/Manhwa/Manhua in (English/Raw) language, Magic series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

A long time ago, books and money had the same value. A teenager who lives in a small remote village with his sister is very eager to go to the book capital. One day he met a secretary and changed his destiny... (Google Translate :P)