What do Muslims believe?

Glossary of arabic terms in this document (in order of appearance):

Allah: this word has no corresponding word in English but is closely translated to mean "The God" and is the proper name for the only Supreme Being who exists by Himself.
Rabb: Lord
Rasool: A Prophet who is given the Book of revealations and Islamic law, and is selected by Allah to pass on his message and be a model for a particular nation.
Sunnah: Tradition (particularly as it relates to the actions of Prophet Muhammed which are in accordance to the commandements of Allah).