This is a book about Taoism

It continues the themes of Lao-tzu and seems to follow what is generally the 2nd half of the Tao-te-Jing which is about ruling a nation. Master Sun approaches war with avoiding a fight if at all possible. You do need read Lao-tzu, Chuang-tzu and the commentaries on this book to see the philosophical milieu of that era. Also the history of the period from the warring states through the Qin and Han dynasties. But this is a convenient reference for the root text.

Richard Cœur de Lion about Sun Tzu’s The Art Of War