McCarthy travels to Tunisia’s heartland, the Sousse region, to understand the mindset of devotees of the country’s major Islamic movement, al Nahda (or Ennahda). The group, led by Rached Ghannouchi, bears much resemblance to Egypt’s Muslim Brotherhood, but McCarthy, who spent two years interviewing members, brings out the major differences. The most important is that after al Nahda’s founding in the 1970s, the group never had time to build up the kind of welfare and educational infrastructure that the Muslim Brotherhood did. As a result, when President Zine el-Abidine Ben Ali crushed al Nahda after it did unexpectedly well in the election of 1989, the group did not have a network to fall back on. What its members did have, as McCarthy masterfully depicts, were the binding experiences of prison and torture, followed by isolation and police surveillance after they were released. In 2016, al Nahda took the radical step of abandoning its mission of religious transformation, known as dawa in Arabic, in order to become an exclusively political party. Liberals applauded the move, but Salafi Islamists saw it as a betrayal. McCarthy shows that many members of al Nahda agreed.