For more than four years, the Arab world has been witnessing profound political and social transformations. These transformations have manifested themselves in a number of popular revolutions and mass uprisings that have swept through several Arab countries, including Tunisia, Egypt, Libya, Algeria, Yemen, Syria, and others. The mass movements in these countries have called at times for broad political reforms and, at other times, for changes in the ruling systems of these countries. These popular uprisings and revolutions have led to the fall of the ruling political regimes in four Arab countries: Tunisia, Egypt, Libya, and Yemen. Meanwhile, protests continue in other countries at the time of writing.