Sharia, (also transliterated from the Arabic as Shar'ia), is the system of jurisprudence and codes from proper conduct drawn from sources including the Qu'ran, traditional (primarily Arab) traditions, the Sunna, and the Hadiths.
Sharia is not strictly Islamic law, which depends strictly on the Qu'ran. Only a small part is irrefutably based upon the core Islamic text, the Koran. Correct designations would be "Muslim Law", "Islam-inspired", "Islam-derived," or even "the law system of Muslims." Sharia is always referred to as "based upon the Koran", hence it is the "will of God."