"THE ROOT CAUSE for the perpetual wandering of beings in sa~psara, tormented by endless suffering, is to hold to an incorrect understanding of the fundamental nature• of phenomena. For this misunderstanding to be purified, the compassionate and skillful Buddha turned the wheel of dharma on inconceivable subjects that are in harmony with the true, fundamental nature ofthings.

To synthesize these teachings, there are two categories: the causal vehicle of characteristics and the vajra vehicle of Secret Mantra. In the vajra vehicle ofSecret Mantra, there are two divisions: the common outer tantras and the uncommon inner tantras. The inner tantras are the three categories of generation·stage Mahayoga: completion-stage Anuyoga,d and the great perfection-stage Atiyoga.• The tantra ofthe Glorious Secret Essence primarily belongs to the category of Mahayoga.

In brief, this commentary [Essence ofClear Light'] gives extremely clear explanations on the topics o f the generation stage, completion stage,  and all the way up through the trekcho instructions of the Great Perfection School. In chis way, since this commentary brings together all the upade- shash of the unsurpassed tantras, it is the epitome of the profound. Just by listening to this profound subject, it is certain that ones mind will be released from its strong hold on ordinary phenomena, needless to mention the benefits of practice."