About Sivananda Paramahamsa
Appa Sivananda Paramahamsa is a yogi with his spiritual skills cured more disease to man kind by providing sidha medicine. Main things is to be follow in the yoga centre a pure vegetarian diet. Because such a diet will give higher qualities of peace, purify, realise and spiritual awareness.

The Book Siddha Vidya
Siddha Vidya was introduced for the first time by His Holiness Swamiji Sivananda Paramahamsa, the divine Preceptor of Preceptors, He is a native of North Malabar. This Vidya by itself is nothing new and swamiji vouches that it ha been practised by our old for there while doing tapas in the forests and mountains of our blessed Motherland. 

The Practise of Siddha Vidya
If you wish to know the secret of siddha vidya you should allow the Lifeforce constantly to traverse in an upward direction in according with the instructions given by the nominal preceptor.Then gradually, in course of time, all your nerves, brain etc. 

This by itself is not the outcome of anythings, but something already in existence. Brahman and Maya have neither a beginning nor an end. It serves no use arguing this out. If anyone were to question as to how smoke 
had its existence in the fire we can only say that the smoke was already in the fire. But, for the outward appearance it is the contrary.