Integral Yoga and Subtle World

Whatever step and direction  one takes in integral yoga it is always into a subtler reality;
the subtle world, the subtle physical, the mental body, are all related with subtle reality, it is not an option, it is a fact.
The subtle world is not related with magic (though it may) nor is an exotic entertainment.
The terms astral world, astral travel, seem to me  improper definitions and I decline to use them, in the subtle world may happen a subtle travel, but it is not the only option there.  I substitute the term  "astral world"   for mental world or level, for the keenness I found  it has with my mental substance. 
The term "astral world" only refers to the objective circumstance and do not take in consideration the main issue: any action or fact there, strictly depend upon our control of the mental body. 
I understand this control during sleep has to be achieved by conscious sleeping, but the subtle reality is perceivable also in wake condition, I have observed that after a reasonable familiarity with the mental body  during sleep,  subtler perceptions start to flow into the wake condition as well, with a clear tendency to create an unbroken stream of perception.
In my own experience it is not a regular process since it´s easily upset by an improper diet,  among other factors.

Our conscious step into subtler reality is by decree accompanied by visible or invisible guides, but guides after all. We step into a training we may not always be conscious of, but a training after all.
If we have reached some degree of consciousness into subtle reality we may remember people and places or happenings we have seen, but our conscious memory of it is not always necessary. 
Many times at wake I could only have faint memories of a subtle experience, while other times I could hold the full sequence of different experiences of one single night.

Any researcher is supposed to reach farther levels of subtlety.
Sri Aurobindo cannot manifest himself into physical matter because if he would and we were witness, we would evaporate in a cloud of atoms,
so he holds a subtle-physical body and we can see him while in the subtle body, which is safer, because more malleable and more resistant to energetic stress.

One can see him in dreams, but the final test will always be in the subtle world.
I do not pretend a treatise on the matter, I speak from personal experience
and what may be useful to know if you have not a clear idea.

The physical body itself has to reach some degree of subtlety, so far, only coming under direct influence of the soul one can hope of "subtilizing" his body,
and as the mind is concerned, it must be able to leave the accustomed circle
of the rational mind and elevate itself into subtler circles, of which the intuitive level is already an expression of the soul and represent some degree of fusion of the lower self with the higher Self.