The Middle Kingdom was formed after a series of wars between the rulers of Upper Egypt (the South) and Lower Egypt (the North). The rulers of Upper Egypt won, and they reunified the country about 2000 BC, with the capital first at Thebes in the south, and then at a new city just south of Memphis. The Pharaohs of this period are not as powerful as before.
They show themselves as taking care of their people, instead of as god-kings as in the Old Kingdom. They are the shepherds of the people now. The nomarchs (local officials) are powerful. In this period, the Pharaohs first started to control places further north of Egypt like Jerusalem, Jericho and Syria. There was a lot of trading with Byblos, near modern Beirut.
Bibliography and further reading about the Egyptian Middle Kingdom:
Eyewitness: Ancient Egypt, by George Hart. Easy reading.
The Oxford History of Ancient Egypt, by Ian Shaw (2002).
History of Ancient Egypt: An Introduction, by Erik Hornung (1999). A college textbook. On the conservative side - not much on new developments.
Ancient Near Eastern History and Culture, by William H. Stiebing (2002). Expensive for a paperback, but brief and very up to date. And yes, it includes Egypt in the Near East.