This book traces the history of OBEs using information from travelers that is still largely available and offers Rogo criticisms of the usefulness of these travelers' techniques to achieve their crossovers. Rogo also uses criticism from other investigators to round out his evaluations. There are numerous methods available to those wishing to stimulate their own OBEs, none of them guaranteed, of course. Rogo himself is an accomplished traveler, which gives his evaluations a lot of weight. It was a relief that he didn't dodge the thoughts of mind scientists who insist that out-of-the-body experiences aren't real, usually leaving the reader to decide. He convinced me that all of the various experiences I've had in this realm have been true OBEs. All of mine seem to have been stimulated by outside conditions and I have been unable to cross over on my own. This frustrates me. I will keep trying. Rogo never mentions Thomas Campbell, who has used OBEs to assemble a most astonishing theory of everything in his "My Big TOE" books and videos, and I find that regrettable. I await the time when I can launch my own out-of-body experiences and won't have to read about them anymore. Until then, this book will be useful and quite readable.