experiences in early societies where they are simpler and, therefore,
more easily understood, and we have followed them up in their
main modifications and complications. We have, moreover, made
use of the comparative method, for it is quite impossible to come
to adequate conclusions in this field by remaining within the pale
of religious life. Such phenomena, for instance, as ecstatic trance
and the impression of illumination become comprehensible only
when they are considered under the diverse conditions in which they
appear, i.e., out of, as well as in, religious life.

The terms, "tendency," "impulse," "instinct," "motive,"
and the like, recur with great frequency in the following pages.
This fact may serve to indicate the point of view from which the
book is written. It proceeds from a dynamic conception of human
nature; it is interested in behaviour and its springs, and it gives a
large place to the non-rational, and to the not-conscious.

In these directions this work falls in line with the recent trends
of psychological science. The author does not, however, accept
the Freudian conceptions in the form in which they are found in the
books of the Viennese physician. The terms of his vocabulary,
libido, introversion, extraversion, complex, psychical compensa-
tion, subconscious activity, conflict, repression, substitution, etc.,
are rarely used in these pages, and yet the discerning reader will not
fail to realize that the facts they designate are among the con-
spicuous facts discussed here.

* * *

This book has been long in the making. My first studies in
religious mysticism were embodied in an essay published in two
parts under the titles, Les Tendances Fondamentales des Mystiques
Chrétiens and Les Tendances Religieuses chez les Mystiques Chrétiens
( Rev. Philos., vol. LIV., 1902, pp. 1-36, 441-87).

Since that time our knowledge has been enriched by a number
of contributions of which I shall mention only those which have been
of particular value to me. First in date and brilliance came the
Varieties of Religious Experience, by William James, 1902; then
H. Delacroix penetrating Etudes d'Histoire et de Psychologie du
Mysticisme, 1908; Friedrich von Hügel conscientious and
sympathetic Mystical Element of Religion as studied in Saint
Catherine of Genoa, 2 vols, 1909. A little later appeared The Meaning
of God in Human Experience, by William E. Hocking, 1912, a
remarkable expression of spiritual discernment served by a rare
literary talent; and, quite recently, five excellent chapters in James B. Pratt's
The Religious Consciousness, 1920. Little of value on
Christian mysticism from the point of view of psychology has been
published in Germany. The book of Joseph Zahn, Einführung in
die Christliche Mystik ( Wissenschaftliche Handbibliothek, 1908) may
be mentioned as of general interest.

Among authors in fields other than 'the psychology of religion,
I owe most to Pierre Janet, of the Collège de France, who from

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