i bought this book (or was it loaned to me?) back in the 60s and remembered it through the years after i had lost of disposed of it. it is very memorable for its treatment of Djinn (genies) and weaves a tale between two universes. very heady stuff, i recommend it for teens or even young at heart over 30 somethings. it was writen by the author of Dianetics series. good SCIFI.