The word "Islam" means "submission", as in "submission to Mohammed's god".
Islam is a throffer religion that was invented by the arab Mohammed ibn Abdullah of the city of Mecca.
Islam's doctrines are given in the book called The Koran, which is the book of Mohammed's official doctrines, and also in The Hadith, which is a collection of books of statements by Mohammed, and records of Mohammed's deeds.
The Koran is primarily egocentric, consisting of numerous threats of end-times judgment and eternal fire-torture to anyone who rejects Mohammed's claim of being the greatest and final prophet of the one and only god, and promises of paradise to those who believe in him and fight on his behalf, which is called "jihad". Aside from that, The Koran is mostly generic devotional boilerplate, some myths recycled from Judaism, and gross redaction of Christianity so as to make it compatible with Islam.
Mohammed and his succeeding rulers, who are called caliphs, and their numerous followers, slaughtered their way across arabia, north africa, iberia, zoroastrian persia, central asia, and christian byzantine anatolia, so as to assert dominance over as much of the world as they can. Their conquests were only halted by the christian franks in western europe, and the hindu indians in the east.