Mrs. Sinclair would seem to be one of the rare persons who have telepathic power in a marked degree and perhaps other supernormal powers. The experiments in telepathy, as reported in the pages of this book, were so remarkably successful as to rank among the very best hitherto reported. The degree of success and the conditions of experiment were such that we can reject them as conclusive evidence of some mode of communication not at present explicable in accepted scientific terms only by assuming that Mr. and Mrs. Sinclair either are grossly stupid, incompetent and careless persons or have deliberately entered upon a conspiracy to deceive the public in a most heartless and reprehensible fashion. I have unfortunately no intimate personal knowledge of Mr. and Mrs. Sinclair; but I am acquainted with some of Mr. Sinclair’s earlier publications; and that acquaintance suffices to convince me, as it should convince any impartial reader, that he is an able and sincere man with a strong sense of right and wrong and of individual responsibility. His record and his writings should secure a wide and respectful hearing for what he has to tell us in the following pages. Mrs. Sinclair’s account of her condition during successful experiments seems to me particularly interesting; for it falls into line with what has been observed by several other workers; namely, they report that a peculiar passive mental state or attitude seems to be a highly favorable, if not an essential, condition of telepathic communication. It would seem that if the faint and unusual telepathic processes are to manifest themselves, the track of the mind must be kept clear of other traffic. Other experiments reported in the book seem to imply some supernormal power of perception of physical things such as is commonly called clairvoyance. It is natural and logical that alleged instances of clairvoyance should have from most of us a reception even more skeptical than that we accord to telepathic claims. After all, a mind at work is an active agent of whose nature and activity our knowledge is very imperfect; and science furnishes us no good reasons for denying that its activity may affect another mind in some fashion utterly obscure to us. But when an experimenter seems to have large success in reading printed words shut in a thick-walled box, words whose identity is unknown to any human being, we seem to be more nearly in a position to assert positively—That cannot occur! For we do seem to know with very fair completeness the possibilities of influence extending from the printed word to the experimenter; and under the conditions all such possibilities seem surely excluded. Yet here also we must keep the open mind, gather the facts, however unintelligible they may seem at present, repeating observations under varied conditions.