孫子兵法; pinyin: Sūnzĭ bīngfǎ) is an ancient Chinese military treatise attributed to Sun Tzu, a high-ranking military general, strategist and tactician, and kindred to the Realpolitik of his time, termed in China as Legalism. The text is composed of 13 chapters, each of which is devoted to one aspect of warfare. It is commonly thought of as a definitive work on military strategy and tactics. It has been the most famous and influential of China's Seven Military Classics, and "for the last two thousand years it remained the most important military treatise in Asia, where even the common people knew it by name." It has had an influence on Eastern and Western military thinking, business tactics, legal strategy and beyond.

Beyond its military and intelligence applications from earliest days to the present time, THE ART OF WAR has been applied to many fields well outside of the military. Much of the text is about how to fight wars without actually having to do battle: it gives tips on how to outsmart one's opponent so that physical battle is not necessary. As such, it has found application as a training guide for many competitive endeavors that do not involve actual combat. There are business books applying its lessons to office politics and corporate strategy. Many companies make the book required reading for their key executives. The book is also popular among Western business management, who have turned to it for inspiration and advice on how to succeed in competitive business situations. It has also been applied to the field of education. The Art of War has been the subject of law books and legal articles on the trial process, including negotiation tactics and trial strategy.