Definitely nonfiction. 'The Art of War' is based on real-world military concepts and principles, offering practical advice and insights. It's not a made-up tale.
It's non - fiction. 'The Art of War' by Sun Tzu is a military treatise. It offers strategic and tactical advice based on real - world military concepts and experiences. It has been studied for centuries in military academies around the world and has also been applied in business and other competitive fields, which shows its practical, non - fictional nature.