Eloquence, three skills, three skills, three reasons and three reasons are different from each other.
The eloquence of three people is different from that of three authors, but these three works were created by three authors in different periods. It's just that some merchants will bundle these three books together when they sell them, which is not related in itself. Cao Xibo wrote "Three Speaks of Eloquence", Mu wrote "Being a Man for Three Sessions" and "Nourishing the Heart for Three Noes".