phenomena?"--_that_, I think, is as yet unsolved, and is likely to
remain so for some time to come. I do not believe that the simple
spiritistic explanation--especially as at present held--is the correct
one, nor one that explains all the facts; for I believe that the
phenomena are more complicated than this. Nor are the ordinary
psychological explanations at present in vogue adequate to cover them.
The explanation is yet to seek; and the solution will only be found when
a sufficient number of facts have been accumulated and the various
explanatory theories have been tested,--to see which of them is really
adequate. My hope is that the present book may help to accomplish this
result by supplying a little in both directions!

The present edition of this book is to some extent an abridgement of the
first edition, which appeared some seven years ago. I have, for
instance, omitted a number of "cases" which were originally included,
and also my "sittings" with Mrs. Piper--which material will be published
at a later date in another volume. I have also omitted the original
First Chapter,--since much of this material was subsequently included in
my _Modern Psychical Phenomena_. On the other hand, I have included a
new chapter on Recent Experiments in Psychic Photography,--composed
partly of original and hitherto unpublished material, and partly of the
experiments undertaken, some years ago, by Dr. Baraduc,--in
"photographing the soul." The account of his experiments was originally
published in my book, _Death: its Causes and Phenomena_, but they are
now included here as being more in line with other experiments recently
undertaken in this field. I have also added a brief chapter on the
Scientific Investigation of Psychic Phenomena by means of Laboratory
Instruments.

A word, finally, as to the necessarily slow progress which has been and
is being made in the study of "psychics." As this objection is often
raised, I cannot do better, perhaps, than to quote an admirable passage
from Prof. William James (_Memories and Studies_, pp. 175-76), where he
says:--

"For twenty-five years I have been in touch with the literature of
psychical research, and have had acquaintance with numerous
'researchers.' I have also spent a good many hours (though far
fewer than I should have spent) in witnessing (or trying to
witness) phenomena. Yet I am theoretically no 'further' than I was
at the beginning; and I con