WHILE we shall take for granted that the reader who has come
so far as to begin this chapter will have a sufficiently open mind
to consider this necessarily brief review of the case for psi, ade-
quate references will be given for any who may wish more ex-
tensive evidence.

In presenting the facts about psi we must, of course, leave the
reader to determine for himself the extent of his acceptance of
them. At the same time, it is taken for granted that any accurate
presentation of evidence on an important question merits atten-
tion, whatever the preconceptions of the reader. Science--we all
like to think--needs and accepts no authority; its course is deter-
mined by its facts. The findings here summarized are receiving
attention, however, not only because of the reliability of the evi-
dence in support of them, but also because they are manifestly
important to many departments of human interest.

After a consideration of the evidence for the establishment of
psi, there will be a review of the different types of psi occurrence
that have been experimentally isolated. There will be left for
succeeding chapters the facts about psi in its relation to the physi-
cal world, about its psychological nature, and its relation to some
of the other fields of science.

It is now safe to say--though only recently so--that the collec-
tions of spontaneous case material themselves constitute valuable
evidence in support of the occurrence of psi. It is quite true that
this material would not be sufficient by itself, but along with the
experimental evidence it offers a very considerable amount of

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