The nations of South and Central Asia are as fascinating as they are diverse. Ranging from the former Soviet Republics of Central Asia to war-torn Afghanistan to the tiny mountain nation of Bhutan to the world's second-most populous country, India, the region has been shaped by millennia of conquest, population migration, and, most recently, global geopolitics. The challenges currently facing South and Central Asia, which include overpopulation, food security, environmental degradation, and the ongoing search for democracy, are as diverse as the nations themselves. However, great progress has been made in recent years, and the picture is improving. More people in this region have access to clean water, food, and education than ever before-though many challenges are still ongoing. In particular, Islamic extremist groups based in this area pose a security threat not only to the nation-states of South and Central Asia, but to the entire world.