Unlike the Negev, the Judean Desert is not part of the world desert stripes of the subtropical latitudes. It is a rain shadow desert, which basically means that hot air with moisture raise from the Mediterranean and go all the way up the Judean hills where it creates rain clouds. As it goes to over the peak of the ridge and descending towards the Dead Sea the air is getting warm again and doesn't create rain clouds anymore.
You can watch here an animation.
While driving from Jerusalem to the Dead Sea it can be easily seen how the scenery is changing dramatically once you start descending to the east. As The desert plateau gets to the Dead Sea Valley, it drops in a big cliff from 200 meters above Sea level to -400 meters to the lowest place on earth. It all creates a very dramatic and beautiful landscape.
Because of the harsh environmental conditions, the place was used mainly as a getaway place for outlaws and rebellions who found their home and base for activity in the caves of the desert. Most famous of them is King David who ran away from Saul before he became the king himself.
There are findings of human presence from the Chalcolithic period. In the 7th century, there was a Jewish village which was famous for it high-quality Afarsemon oil, This oil was famous in the ancient world. In Ein Gedi you can see the remains of an old synagogue which are is special. It has a mosaic which contains an inscription with a curse upon the people who will reveal the town's secret. Researchers believe that the secret is the way of producing the famous Afarsemon oil.
The synagogue also has a mosaic with …..a swastika!
No, they were not Nazis, it was just a common symbol in synagogues back then.
In the time of the second temple, the place was the home to the Essenes who were a sect of Judaism who wanted to distinguish themselves from the rulers in Jerusalem. The Essenes became known with the finding of the famous Dead Sea scrolls.
You can see some of the Scrolls in the Israel Museum in Jerusalem.
Land of the Monasteries
Because of its relatively short distance to Jerusalem and isolated conditions, the place became an ideal place for people who were seeking for the monastery life. Many scattered along the area. You can visit some in Wadi-Qelt and Qasr Al-Yahud.