While the first volume of the Foundation of Yoga deals with the historical side of the foundation, the present one concerns itself with the psychological which has been discerned in the form of consciousness. Just as matter is the basic stuff physical sciences have to deal with, consciousness serves as the basic stuff of the science of spirit known as Yoga. Any yogic practice apart from deep understanding of the nature of consciousness is, thus, doomed to end in an exercise in futility. This is what has been brought to the fore by Vedic seers and Upanisadic sages practically by diving deep into consciousness and declaring it as the source of everything in the world including matter itself. As such, what modern psychologists have declared as sub-conscious and unconscious, is only a covert form of consciousness. What has recounted in the Veda as was between gods and demons is, thus, reducible to the seer’s entry into these covert layers of consciousness and facing the odds. Search of one’s identity in the pure consciousness is liberation and immortality while one’s identification with the physical is bondage and mortality. The Mahamrtynjaya matra epitomizes this secret at its best. All this has been brought out here closely and cogently on the evidence of the galaxy of Vedic seers and Upanisadic sages with a view to recreate the real psychological foundation of Yoga which otherwise is being tossed around today like a kite snapped off its string. As such, the volume is expected off its string. As such, the volume is expected to prove an authentic passage to entry into the citadel of yoga and experience the felicity lying await within. It will be helpful in clearing the cobweb of misunderstanding about it formed in course of millennia and will benefit everyone including yoga teachers, practitioners, researches and students who are doing graduation, post-graduation and Ph.D. in Yoga.