i'm just talking about the fundamental beliefs of the religion steve, not specifics.
islam believes in one god, who created adam and eve and after that sent messengers/teachers to mankind to teach them morality and goodness, e.g. noah, jacob, joseph, lot, abraham, moses, jesus, etc. with muhammad being the last of the chain.
judaism believes the same thing but they stopped short at moses and are still waiting for the messiah (who muslims recognize as jesus)
christians also recognize jesus as the messiah, a teacher, but also worship him, they see him as equal to god. that's something that's rabbi's go nuts over, let alone imams.