These are called the borderlands since the Middle East is in fact on the border between continents and cultures. Across these lands have passed many an army since ancient times. To the east is the heart of Asia. To the northwest are the nations of Europe. To the southwest is Africa. Whether 2,000 years ago or today, these lands seem to be the focus of much of the world's conflicts.
The nations and boundaries of today's Middle East are in major part (1) creations by the victorious European nations following the end of World War I and the breakup of the Ottoman Empire and (2) actions by the British relating to their former colonial possessions in India and North Africa. The resultant mess has created one great headache for the area's inhabitants and the rest of the world.
The Middle East imagined here is primarily organized into four great federations of nations: Egyptian, Iranian, Semitic, and Turkic. The common thread uniting these federations is a language family. Two of the federations, Semitic and Egypt, have a common language, Arab, but are split for cultural, ethnic and geographic reasons.
Ethnic groups within the federations having at least 10 million members (with some exceptions) are designated as distinct republics on the map. Republics which may not fit easily into the four federations for historical reasons are imagined as Autonomous Nation States.
The Kurd Autonomous Republic is one such instance. Israel and a smaller Lebanon are two others. Although it is possible in 200 years that these last two might be peaceably integrated into a Semitic Federation.
The rationale for the imagined nations and boundaries is covered in more detail below.