Tao Te Ching or Dao De Jing
Originally known as Laozi, is a Chinese classic text.
Written around the 6th century BC by the Taoist sage Lao Tzu, the Tao Te Ching is the fundamental text of the Taoist school of Chinese philosophy. The 81 chapters of short but profound verses teach Lao Tzu's timeless observations about life and the nature of being.
Here's an excerpt from the book:
"He who knows other men is discerning; he who knows himself is intelligent. He who overcomes others is strong; he who overcomes himself is mighty. He who is satisfied with his lot is rich; he who goes on acting with energy has a firm will.
He who does not fail in the requirements of his position, continues long; he who dies and yet does not perish, has longevity."
The Tao Te Ching is fundamental to the Philosophical Taoism and strongly influenced other schools, such as Legalism and Neo-Confucianism. This ancient book is also central in Chinese religion, not only for Religious Taoism but Chinese Buddhism, which when first introduced into China was largely interpreted through the use of Taoist words and concepts. Many Chinese artists, including poets, painters, calligraphers, and even gardeners have used the Tao Te Ching as a source of inspiration. Its influence has also spread widely outside East Asia, aided by hundreds of translations into Western languages.
The Wade-Giles romanization, Tao Te Ching, dates back to early English transliterations in the late 19th century, and many people continue using it, especially for words and phrases that have become well-established in English. The pinyin romanization Daodejing originated in the late 20th century, and this romanization is becoming increasingly popular, having been adopted as the official system by the Chinese government. (Source: wikipedia)