It contains almost everything an emperor/ general needs to rule a country or an army. From agriculture to political strategies, military affairs to geographic science, moreover, it provides interesting and yet proven to be effective numerology, which has led to controversial arguments for years. I've read about 70- 80 Chinese traditional military books and this is one of my two favs. The other is <反经> (), also written in the Tang Dynasty. One of the reasons I love about these two books is that it provides knowledge not only powerful in politics/ military but also handy in everyday life.