Yogi Ramacharaka 
The Hindu-Yogi Science Of Breath [EPUB ebook] 

This book gives you step-by-step instructions on the art of the breath. It is a great addition to anyone’s library if you’re interested in spirituality and meditation.

If you read and do the exercises in this book, amazing changes will result in your mind and body. These exercises are deceptive they don’t seem impressive, any person, any child could do them, so it goes without saying most people will lose interest because it doesn’t seem arcane enough. Those who do the work will be amazed by what results.