There are various interpretations of Self; for example: there is the Self of Ego, the Self called Soul, the Hindu Atman and a universal Self.
Whatever the theories – Self is the core and in a certain way the coordinate of every human being.
Possibly due to the difficulties of defining Self, the relationship with its beholder gets sometimes stressed – even so far, that latter doubts the presence of prior.
But Self is vital as it knows the true nature and needs of its beholder and thus becomes particular important when turmoil and confusion threaten its physical & mental wellbeing.
There are many unification teachings, but most of them focus on a higher instead on a common Self, despite that we are selfish creatures and thus foremost interested in our own troubles, and who is more qualified to handle them but Self.