The name
Yijing (易經) means "Classic of Changes." 易 is change, and 經 is the warp of a woven cloth and, by extension, a canonical book. I Ching is the same word spelled in the older Wade-Giles romanization; Yijing is the pinyin spelling used today.
What it's made of
- The Zhouyi: the 64 hexagram figures with their judgments and lines.
- The Ten Wings: the commentaries that explain them.
How it became a classic
In 136 BCE the Han court set up five official classics, and the book of changes headed the list. From then on it was studied as a book of wisdom, not just a manual for consulting. Confucian, Daoist and Buddhist thinkers wrote on it for centuries.
In the West
Jesuit missionaries brought it to Europe's attention in the 17th and 18th centuries. Leibniz saw in the hexagrams a likeness to his binary arithmetic. In the 20th century, new translations and Carl Jung's foreword, with his idea of synchronicity, made it popular with readers everywhere. The full story is in The History of the I Ching.
How to use it
You can read it straight through, but most people consult it: you ask a question, get a hexagram and read what it says. It doesn't foretell the future; it gives you another way to look at where you stand. Start with What Is the I Ching?.