It was not gods that concerned him, but the mind of man and its sorrowing. We are unhappy, he explained, because we are slaves to our desires. Extinguish desire and suffering goes with it. If people could be taught that the physical or phenomenal world is illusion, then they would cease their attachment to it, thereby finding release from their self-destructive mental bondage. The Buddha neglected to set down these ideas in written form however, perhaps unwisely leaving this task to later generations. His teachings subsequently were recreated in the form of sermons or sutras. In later years, the Buddhist movement split into two separate philosophical camps, known today as Theravada and Mahayana. The Theravada Buddhists-- found primarily in southeast Asia, Sri Lanka, and Burma--venerate the early writings of Buddhism (known today as the Pali Canon) and tend to content themselves with practicing the philosophy of the Buddha rather than enlarging upon it with speculative commentaries. By contrast, the followers of Mahayana--who include the bulk of all Buddhists in China, Japan, and Tibet--left the simple prescriptions of the Buddha far behind in their creation of a vast new literature (in Sanskrit, Tibetan, and Chinese) of complex theologies. Chinese Ch'an grew out of Mahayana, as of course did Japanese Zen. NAGARJUNA After the Buddha, perhaps the most important Buddhist figure is the second-century A.D. Indian philosopher Nagarjuna. Some call him the most important thinker Asia has produced. According to Tibetan legends his parents sent him away from home at seven because an astrologer had predicted his early death and they wished to be spared the sight. But he broke the spell by entering Buddhist orders, and went on to become the faith's foremost philosopher. Today Nagarjuna is famous for his analysis of the so-called Wisdom Books of Mahayana, a set of Sanskrit sutras composed between 100 B.C. and A.D. 100. (Included in this category are The Perfection of Wisdom in 8,000 Lines, as well as the Diamond Sutra and Heart Sutra, both essential scriptures of Zen.) Nagarjuna was the originator of the Middle Path, so named because it strove to define a middle ground between affirmation of the world and complete negation of existence.