This text investigates the core methods and philosophical frameworks required for achieving enlightenment, or Nirvana, through the lens of Tibetan Buddhist tradition. W. Y. Evans-Wentz, a pioneer in the study of Tibetan religious texts, compiles and translates these teachings to bridge the gap between Eastern esoteric practices and Western academic understanding. The work argues that the realization of the ultimate nature of mind is a systematic process accessible through specific meditative techniques and philosophical inquiry.

Scholars and practitioners frequently cite this work as a foundational, albeit dense, introduction to Tibetan esoteric traditions for Western readers. While some modern academics critique the editor's interpretive framework, the text remains a significant historical document in the field of comparative religion.