This work is one of three on yoga by the same author, under his chosen pseudonym, presumed to actually be William Atkinson. It is a fairly detailed description of Raja yoga (or royal yoga) and centers around self awareness, mental focus, and exercises designed to increase both of the same. While a few of the tales here (Houdin is explicitly spoken of) are hyperbolic, the text is, altogether, well written, and was designed for serious students of yoga to understand this particular distinct branch of the same.