Islam, Christianity and Judaism are all monotheist religions. All three religions acknowledge some parts of the Bible as the word of God. Muslims believe the word has been changed or modified and therefore not necessarily valid and Jews accept the first 5 books of the Bible's Old Testament as their holy book, the Torah. Muslims accept Jesus as a prophet and not the son of God and do believe as Christians do that he can return. As you stated, there are many similarities between Christianity and Islam, however those similarities also exist between all three monotheist religions.
