Maandookyopanishat

Maandookyopanishat: There are only 12 mantras in this upanishat. But it gives great secrets of vedaanta. pranavam ie om kaaram is combination of a+u+m=om, is given here.  Just like om kaaram has behind the stage out of aa, vu and ma, bhagavaan or aatmaa or chaitanyam takes stage of witness / shaakshee bhootam during the three stages of human-jaagrat, svapna and sushupti, om also is in same position from a+u+m. That tureeyaavastha is only stage for human to get brahmaananda. The chaitanyam is known by name as vaishvaanara, taijasa, pragnaa and shiva in all these four stages respectively. gaudapaadaacharya the guru of guru of aadi shankaraacharya has given excellent kaarikaa for this upanishat which has become a basis for advaita sidhaanta promoted by aadi shankara.