The science of modern yoga, more truly, is a cycle of sciences of yoga, will consist of the description of the methods adapted to people of different types and different ability to live, and from an explanation of the theories connected to these methods.
Each of the sciences making yoga breaks up to two parts: theoretical and practical. The theoretical part is in a coherent and integral kind, not going deep in unnecessary details, states main principles and general provisions of the given subject. The practical part teaches ways and receptions of the best preparation for desirable activity, methods and means of development of the latent forces and abilities.
The science of yoga long time was kept in India as fiduciary. Science yoga in the west appeared only recently. Those methods, which in almost wonderful image increases force of the person, were the privilege of scientists Brahmin the highest caste or devotees and the eremites who have completely renounced from the world. In the Indian temples, there were schools where pupils past a long way of tests and preparatory training, were devoted in a science of yoga by special teachers - the guru.
Europeans could not receive any data on yoga; this is why modern yoga is completely classical and original. Everything, that travelers usually told had completely fantastic character. The first authentic data on yoga have started to appear only in second half 19th centuries though in mystical societies many methods of yoga were known much earlier. The modern growth of yoga happen thanks to borrowing at yogis, all the same could not understand and capture all sense of a science of yoga in its set.
Actually, the yoga is a key to all ancient wisdom of the East. The ancient books of India full of deep wisdom, until now are not clear the western scientist. That is why modern yoga should not only develop and move ahead, but also make people turn around and see the science and wisdom of ancient Indians.
The modern yoga indefinitely increases forces of the person in struggle against a life (i.e. against all physical conditions in which the person will be born also which are hostile to) and in struggle against the nature, always aspiring to use the person for the purposes. In the third, it increases the man's forces in struggle against illusions of his own consciousness, which, being in dependence from the limited mental device creates infinite set of Mirages and deceits.
The yoga helps the person to struggle from deceits of words, clearly showing him that the idea expressed by words cannot be true, that in words of true is not present, that, at the best, they can hint only at true, show it for one instant and there and then hide. The yoga teaches how to find the true latent in things, in affairs of people, in books of great wise men of all times and peoples. Five yogis are the five ways leading to one purpose - to perfection, to transition to the supreme steps of knowledge and a life.
The division into five yogis depends on the division of people into types, the specific abilities of people and their preparation. Only then will they start the journey to true enlightenment.