The evolutionary path of every human soul consists of stages. One cannot come to spiritual Perfection all at once.
Since ancient times, there exist methods for development of the body with its energy structures and the mind, and then — for development of the consciousness. We can find such methods in all advanced traditions of spiritual culture.
Patanjali described in detail the stages of such an ascent in his Ashtanga Yoga.
There is also the following scheme of spiritual training in the psychoenergetical aspect of development: Hatha Yoga — Raja Yoga — Buddhi Yoga.
Here, Hatha Yoga is a preliminary stage, which allows one to improve the health of the body and to learn basic skills of concentrating the mind and moving the consciousness within the body.
Raja Yoga is a system of methods for cleansing and development of the chakras and main meridians. That is, the work on this stage is performed within the body and the energy cocoon around the body.
And Buddhi Yoga is a system of methods for developing the consciousness outside the body — when the consciousness becomes free from the “fetters” of matter, moves in the multidimensional space, and learns to communicate directly (not through the bodily organs of sense) with Divine Teachers — Holy Spirits.
Mastering the stage of Raja Yoga can lead one to Samadhi: a high emotional state of Bliss, which occurs from a contact of an individual consciousness with God in the Aspect of the Holy Spirit (Brahman).
On the stage of Buddhi Yoga, one cognizes Nirvana (Mergence with the Divine Consciousness and “dissolution”, disappearance of the individual “I”) in Brahman and then in Ishvara (the Creator, God-the-Father, the Primordial Consciousness).
Let me note that the Sanskrit word yoga means the same as the Latin word religion. One should interpret both of these terms as the Path of spiritual development — up to direct personal cognition of the Creator and Mergence with Him.
In this book, we discuss mainly the higher stages of this Path, that is the stages of Buddhi Yoga.