Ahem - People - kindly look at the TITLE of this THREAD.
Here's a short synopsis:
Islam is monotheistic, totally. In that respect, it is 'closer' to Judaism.
However, Islam views 'faith' as primary, with a final judgement day sending souls to eternal heaven or eternal hell based on (mostly) proper faith. 'Correct belief' is vital, in other words. In THIS respect, Islam is 'closer' to Christianity.
Islam considers the characters of the Hebrew Bible to also be characters of Islamic scripture - and routinely consider Abraham, Ishmael, Jacob, the prophets etc to be Muslim, because 'Muslim' means someone who submits to God's will, not just people who follow Mohammed.
Mohammed is the LAST Prophet, and the one who 'returned' to the proper original Way, because both Judaism and Christianity - well all very well in their way - got it wrong ('corrupted the faith').
Jesus is a prophet in Islam.
Islam teaches that Jesus was a prophet of God, the messiah, but did NOT die on the cross, nor was he resurrected (because you don't have to be resurrected if you didn't DIE).
The stories of Abraham nearly sacrificing his son on the mountain is in the Qu'ran, but the son is (or is assumed to be) Ishmael, not Isaac.
Abraham and his son Ishmael are credited with building the Ka'aba in Mecca.
Job, Lot, Jonah etc - these are all 'prophets' in Islam.
The Islamic view of a prophet is different from the Jewish (or Christian) view. In Islam, prophets are PERFECT. They can do no wrong. They are never incorrect.
We have a bit of an issue with that - who among Jewish or Christian circles would view, for instance, LOT, as a perfect and sinless person?
Islam rests on 'the Five Pillars' of faith - the ideal Muslim will observe/practice these Five Pillars:
1 -Profession of Faith "There is no god but God, and Muhammad is the Messenger of God" Reciting that (and meaning it) constitutes conversion to Islam, and it is a central core prayer statement of Islam.
2 -Prayer - ideally, five times daily (nomads and travelers get a break - only three times). Prayer involves prostration (bowing to the ground to God), and worshippers face in the direction of Mecca (or if in Mecca, in the direction of the Ka'aba).
3 -Alms - it is a requirement to donate for the poor in Islam. (It is also illegal to charge interest on loans, and Muslim communities get around that in various ways, but typically through no-interest community funding for things most Americans would take out loans for - like mortgages and businesses).
4 -Fasting - it is a requirement to fast during the daylight hours during the month of Ramadan
5 -Pilgrimage - it is desirable, if not absolutely required, that every Muslim who can manage it, should make the pilgrimage to Mecca once in their lives.
Islam means something like 'submission' as in submitting to the will of God. The ideal Muslim will 'submit' to God's will, and God determines everything and knows everything. Everything is according to the will of God.
This is rather different from the Jewish view, which values a tradition starting with Abraham, of ARGUING with God, wrestling with God, passionately debating about exactly what God's will actually IS - 'Israel' means 'wrestler/contender with God', after all. Free will, in this view, is TOTALLY free: reward and punishment are not tightly linked to individual decisions, and in any case, do not (or shouldn't) affect things immediately - the rain falls on the just and the unjust. God has told us what he wants, but we are free to make our own decisions.
This is even different from the Christian view, which is much more subservient to God than the Judaic approach. Christians would agree that one should 'submit' to God, but would probably not agree that man has no free will to choose at all. Christianity has a far more dire opinion of sin, and divine punishment, that mainstream Judaism (you will find plenty of Jews with a somewhat more dire opinion, mostly among the ultra-orthodox).
Analogy -
If Christianity in the main, has a somewhat black/white approach to things, with shades of gray subordinate to that, then Judaism is FAR more gray and a lot less black and white, while Islam is almost entirely black and white, with almost no gray at all, and not much space for any.
Sufism is a mystical philosophy within Islam, and like any mysticism, is neither black, white nor gray, but rainbows.
There are two major branches within Islam, dating back to the ninth? I think ninth - century CE: Sunni Islam, and Shia Islam (followers known as Shi-ites).
Sunni Islam is the majority; Shia is not as widespread, but it is the major branch of Islam in several countries, especially Iran and Iraq.
It would be a mistake to think that division is equivalent to the break between Catholicism and Protestantism. It is more like the break between Eastern Orthodox and Roman Catholicism - the two branches are actually VERY close in a lot of ways, but have some significant theological differences going back to VERY early in the history of Islam. They have fought wars over it.
The US 'Black Muslim' movement began mainly as a rejection of Christianity among blacks, as a religion imposed by slavemasters. Islam was seen as more of a native African faith (and it is important in Africa). However, the Black Muslim movement did not have very many actual Muslims to look to, and developed a bit idiosyncratically - at least at first. Malcolm X made the pilgrimage (Hajj) to Mecca, however, in 1964. During that trip, he encountered hundreds of thousands of fellow pilgrims, who were of all races and skin colors, and discovered 'normal' Islamic faith and practice.
https://www.thoughtco.com/malcom-x-in-mecca-2353496
Some have said that his attempts to move the Black Muslims closer to world Islamic norms is what got him assassinated, as he moved away from a racist position which was important in the early Black Muslim days during the Civil Rights movement in the US. I don't know about that.
I believe, however, that the current Black Muslim movement in the US actually IS much closer to 'normal' Islamic practice, but I don't know for certain. BH should have something to say now.