When we study the early cultures of the Ancient Near East, we learn that many of them were Semitic - just as many cultures in that same location today are Semitic. But what is Semitic?
First of all, let's clarify a common misunderstanding: "Semitic" is not another word for "Jewish"! Some people use "anti-Semitic" to mean "anti-Jewish," but those two terms actually have different meanings. For example, an Arab is a Semite, and therefore an Arab cannot be anti-Semitic, however much he may hate Jews.
All the cultures which are Semitic share a common cultural base, including linguistic elements and artistic traditions - music, stories, food, clothing, etc.
There was once only one group of Semitic people: scientists call this "Ur-Semitic" or "Proto-Semitic," and gradually, over time, this group broke into smaller groups: Arabs, Egyptians, Assyrians, Babylonians, Ethiopians, Hebrews, Canaanites, Phoenicians, Urgaritic, Aramaic, and Akkadian. These are the Semitic groups, in ancient times, as well as now. To this day, there are similarities between the Hebrew and Arabic languages.
Important to note are those groups which are not Semitic, and therefore are closely related to European languages like German and Russian: Hittite, Sanskrit, and Persian. Modern-day Iranians are Persians, not Arabs, and therefore not Semitic.
Understanding who's Semitic and who's Indo-European will help you understand the dynamics of the Ancient Near East, and perhaps also the Modern Near East!