<p>"The study of mysticism in the twentieth century has moved back and forth from those who posit a basic unity to the mystical experience to those who emphasize diversity. Those who favor the latter position have been somewhat in ascendance since the work of Steven Katz. But valuable as it is as a critique, Katz's position of seemingly irreducible diversity really does not have much positive to give us in understanding what the mystical experience may have to offer. Dan Merkur's typology is a real step forward in that he suggests that there may be a coherent overall pattern to heightened or altered states of consciousness. I am not saying that Merkur's work is 'the last word' on the subject. Au contraire, it is the first word in what should prove to be a very fruitful line of inquiry."— James Burnell Robinson, University of Northern Iowa</p><p>"The book is well organized, clearly written, well researched, on a topic that is significant and interesting. The author reveals considerable insight into the subject matter." — Steven Katz, State Technical Institute at Memphis</p>