Mr. Gu studied under many teachers, such as Wu Huichuan, Wu, Chen Fake and so on, and read all of them. But whether he really taught him real skills, only Mr. Gu knows.

My suggestion is that you don't have to read Mr. Gu's books. Because Mr. Gu's inner strength hasn't reached his upper body yet. This is not a deliberate denial of the former sages, but a fear of delaying their studies and having to defend themselves.

You can read books by Mr Li Yaxuan, Mr Sun Cunzhou, Mr Sun Lutang and Mr Wang Yongquan. That's the right way.