This may be a fine book with lots of great pathworkings - I don't know because I'll never buy it. My reason was provided in the first few pages, helpfully provided with the "look inside" feature. In these, the author goes to great lengths to disparage boring old scientific rationality and starts by laughing at the risible theory that mind is simply the interaction of millions of brain cells.
In fact it is estimated that there are around 100 billion neurons in the human brain with around 100 trillion synapses, making it one of the most complicated structures in the known universe. It therefore seems entirely possible that consciousness is an epiphenomenon of this complexity but that would not undermine the power or usefulness of magical exercises, in the same way that knowing the underlying neurobiological mechanisms of Love does not diminish our experience of it.
However, if the author can make such an embarrassing and glaring error in the first few pages, I find myself disinclined to follow him any further in his pseudo-scientific mysticism.