The study of Asian history includes covering a range of topics that cover the world’s largest and most diverse continent. The fact that it occupies the eastern four-fifths of the giant Eurasian landmass lends itself to creating enormous diversity that surpasses other regions of the world. Geographically, Asia has both the highest and the lowest points on the surface of Earth, has the longest coastline of any continent, is subject overall to the world’s widest climatic extremes, and, consequently, produces the most varied forms of vegetation and animal life on Earth. In addition, the peoples of Asia have established the broadest variety of human adaptation found on any of the continents.
Asia is one of the most populous of the continents, it contains some three-fifths of the world’s people. Asia’s uniqueness is not limited to its geography or density of population, it is unique for being the birthplace of all the world’s major religions—Buddhism, Christianity, Hinduism, Islam, and Judaism. Of those, only Christianity developed primarily outside of Asia; it exerts little influence on the continent, though many Asian countries have Christian minorities. Buddhism has had a greater impact outside its birthplace in India and is prevalent in various forms in China, South Korea, Japan, the Southeast Asian countries, and Sri Lanka. Islam has spread out of Arabia eastward to South and Southeast Asia. Hinduism has been mostly confined to the Indian subcontinent.