Book excerpt: A land of enormous proportions, countless secrets, and incredible history, Central Asia was the heart of the great Mongol empire of Tamerlane and scene of Stalin's cruelest deportations. A remote and fascinating region in a constant state of transition—never more so than since the collapse of the Soviet Union—it encompasses terrain as diverse as the Kazakh steppes, the Karakum desert, and the Pamir mountains. In The Lost Heart of Asia, acclaimed, bestselling travel writer Colin Thubron carries readers on an extraordinary journey through this little understood, rarely visited, yet increasingly important corner of the world.