Making sense of Saudi Arabia is crucially important today. The kingdom's western province contains the heart of Islam, its two holiest mosques in Mecca and Medina, and it is the United States' closest Arab ally and the largest producer of oil in the world. However, the country is undergoing rapid change: its aged leadership is ceding power to a new generation, and its society, which is dominated by young people, is restive. Saudi Arabia has long remained closed to foreign scholars, with a select few academics allowed into the kingdom over the past decade. In his latest book published in 2014, Saudi Arabia in Transition: Insights on Social, Political, Economic and Religious Change, Bernard Haykel examines the different sectors of Saudi society and how the past few decades have affected each.