What is the theme in The Teachings of Don Juan: A Yaqui Way of Knowledge by Carlos Castaneda?

The Teachings of Don Juan deals with the dynamic of apprenticeship, in which master teacher and protygy must exercise the highest degree of attentiveness. The teacher, Don Juan Matus, is the heir to a spiritual tradition going back generations. He must evaluate everyone he meets to see if he is capable of carrying on the tradition. In the case of Carlos Castaneda, who first appears to him as a rather brash academician seeking information about peyote, Matus must overlook eagerness and curiosity to discern whether he has the "backbone" to stand up to Mescalito, the anthropomorphic persona of peyote.