Chapter 48 lists several types of individuals who should not be considered Sadgurus. Can you summarize who these are?

Certainly. To clarify the true nature of a Sadguru, Chapter 48 first outlines what a Sadguru is not. According to the wise, one should not automatically consider someone a Sadguru just because they have studied the Vedas, mastered the six Shastras, or can explain Vedanta. The chapter also dismisses those who focus on external practices like controlling the breath (Pranayama) or wearing heated marks (Taptamudra). As detailed in Chapter 48, even those who can please an audience with talks about Brahman or give out scriptural mantras are not true Sadgurus if they lack direct, personal experience, as their knowledge is merely 'verbally hollow.'