Sri Aurobindo
Letters on Yoga
5. Planes and Parts of the Being
The subconscient is universal as well as individual like all the other main parts of the Nature. But there are different parts or planes of the subconscient. All upon earth is based on the Inconscient as it is called, though it is not really inconscient at all, but rather a complete “sub”-conscience, a suppressed or involved consciousness, in which there is everything but nothing is formulated or expressed. The subconscient lies between this Inconscient and the conscious mind, life and body. It contains the potentiality of all the primitive reactions to life which struggle out to the surface from the dull and inert strands of Matter and form by a constant development a slowly evolving and self-formulating consciousness; it contains them not as ideas, perceptions or conscious reactions but as the fluid substance of these things. But also all that is consciously experienced sinks down into the subconscient, not as precise though submerged memories but as obscure yet obstinate impressions of experience, and these can come up at any time as dreams, as mechanical repetitions of past thought, feelings, action, etc., as “complexes” 
exploding into action and event, etc., etc. The subconscient is the main cause why all things repeat themselves and nothing ever gets changed except in appearance. It is the cause why people say character cannot be changed, the cause also of the constant return of things one hoped to have got rid of for ever. All seeds are there and all Sanskaras of the mind, vital and body,– it is the main support of death and disease and the last fortress (seemingly impregnable) of the Ignorance. All too that is suppressed without being wholly got rid of sinks down there and remains as seed ready to surge up or sprout up at any moment.
Current publication:
Sri Aurobindo. Letters on Yoga // SABCL.- Volume 22. (≈ 28 vol. of CWSA).- Pondicherry: Sri Aurobindo Ashram, 1971.- 502 p.
Other publications:
1. 5440.
[A letter: ] Sri Aurobindo; Nirodbaran Nirodbaran Talukdar. Correspondence with Sri Aurobindo: The Complete Set [in 2 volumes].- 2nd ed., 3d inpression.- Volume 1.- Pondicherry: Sri Aurobindo Ashram, 2001.- 602 p.
2. 10223.
Sri Aurobindo. Letters on Yoga. I // CWSA.- Volume 28. (≈ 22 vol. of SABCL).- Pondicherry: Sri Aurobindo Ashram, 2012.- 590 p.
3. 22287.
Sri Aurobindo. Bases of Yoga [: Extracts from letters].– Seventh Edition, 1955.– Pondicherry.– Sri Aurobindo Ashram, 1955.– 133p.