The I Ching (Wade-Giles), or "Yi Jing" (Pinyin); also called "Book of Changes" or "Classic of Changes") is the oldest of the Chinese classic texts. A symbol system designed to identify order in what seem like chance events, it describes an ancient system of cosmology and philosophy that is at the heart of Chinese cultural beliefs. The philosophy centres on the ideas of the dynamic balance of opposites, the evolution of events as a process, and acceptance of the inevitability of change (see Philosophy, below). In Western cultures, the I Ching is regarded by some as simply a system of divination; many believe it expresses the wisdom and philosophy of ancient China.

(yau), when used as an adjective, means "easy" or "simple", while as a verb it implies "to change" or 'to exchange/substitute one thing for another'. (jing) here means "classic text", derived from its original meaning of "regularity" or "persistency", implying that the text describes the Ultimate Way which will not change throughout the flow of time. This same character was later appropriated to translate the Sanskrit word 'sitra' into Chinese in reference to Buddhist scripture. In this sense the two concepts, in as much as they mean 'treatise,' 'great teaching,' or 'canonical scripture,' are equivalent.

The conception behind this title, thus, is profound. It has three implications:

1. Simplicity - the root of the substance. The fundamental law underlying everything in the universe is utterly plain and simple, no matter how abstruse or complex some things may appear to be. 2. Variability - the use of the substance. Everything in the universe is continually changing. By comprehending this one may realize the importance of flexibility in life and may thus cultivate the proper attitude for dealing with a multiplicity of diverse situations. 3. Persistency - the essence of the substance. While everything in the universe seems to be changing, among the changing tides there is a persistent principle, a central rule, which does not vary with space and time.

Due to the profound ideas conveyed by the title itself, it is practically impossible to arrive at an unbiased translation which could preserve the original concepts intact. The translation of the title into English used to be Book of Changes, though a slightly more accurate name, Classic of Changes, appears more frequently in recent use.