Like other Arab revolutions in 2011, it is said that Yemen's rebellion was modeled on street protests in Tunis and Cairo. As this erudite new study explains, however, what happened in Yemen is far from being a mere echo of events elsewhere. In fact, the popular uprisings which came as a surprise in Tunisia and Egypt, Libya and Syria, were already well underway in Yemen. As early as 2007, this country on the southern tip of the Arabian Peninsula was...