BEIRUT — A great menace hovers over the Arab region and its people, and has started to nibble away at their societies and countries. Our region now is made up mostly of poor and vulnerable families, and it is corroding and fragmenting from within. Unlike the popular media images abroad of vast Arab wealth, the reality is the exact opposite. The Arab region is fracturing and disaggregating into a small group of wealthy people, a shrinking middle class, and masses of poor, vulnerable, and marginalized people who now account for 2/3 of all Arabs. Some 250 million people, out of a total Arab population of 400 million, are poor, vulnerable, and marginalized, according to important new research by Arab and international organizations.