Han Fei Tzu (280?-233 B.C.) was a prince of the ruling house of the small state of Han. A representative of the Fa-chia, or Legalist, school of philosophy, he produced the final and most readable exposition of its theories. Ironically, Han Fei Tzu's advice was heeded not by the king of Han but by the king of Ch'in, who, soon after ascending the throne in 246 B.C., conquered all of China and, as First Emperor of the Ch'in, established the Ch'in dynasty. Han Fei Tzu, sent as an envoy to Ch'in in 234 B.C., was at first welcomed by the king but later, on a royal minister's urging, was cast into prison, where he committed suicide. Han Fei Tzu's handbook for the ruler, which includes a few chapters for the guidance of his ministers, deals with the problem of preserving and strengthening the state. There are sections on the way of the ruler, on standards, on the use of power and of punishment and favor. Dangers to be avoided by the ruler are specified, as are precautions to be taken. Witty, trenchant, sophisticated, and cynical, the Han Fei Tzu has been read in every age. It retains its interest today when, perhaps more than ever before, men are concerned with the nature and use of power.