Whenever you see a publication From Paramahansa Yogananda you can be certain it is has to do with the organizations he founded SRF in the USA and abroad and YSS in India and the specific form of Kriya Sadhana he taught.
To discover more concerning what you have asked about you can by reading Autobiography of a Yogi it can be found in the 1950's format on line for free.
If you feel a connection you can pursue further knowledge from either of these organizations but 1 small booklet contains no silver bullets just an intro if you will, like a free sample to get you to purchase the meal.