be compared with specimens of mollusks
that live to-day. Down through the countless centuries the living stream
has carved its structural habitations in much the same form. The science
of Paleontology has collected this history and has attempted a
reconstruction of life from its beginnings.

The same principle here illustrated is true for the thought-life of
mankind. The forms in which it has been preserved however are not so
evident. The structuralizations are not so definite. If they were,
evolution would not have been possible for the living stream of energy
which is utilized by mind-stuff cannot be confined if it would advance to
more complex integrations. Hence the products of mind in evolution are
more plastic--more subtle and more changing. They are to be found in the
myths and the folk-lore of ancient peoples, the poetry, dramatic art, and
the language of later races. From age to age however the strivings
continue the same. The living vessels must continue and the products
express the most fundamental strivings, in varying though related forms.

We thus arrive at a science which may be called paleo-psychology. Its
fossils are the thought-forms throughout the ages, and such a science
seeks to show fundamental likenesses behind the more superficial
dissimilarities.

The present work is a contribution to such a science in that it shows the
essential relationships of what is found in the unconscious of present day
mankind to many forms of thinking of the middle ages. These same trends
are present to-day in all of us though hidden behind a different set of
structural terms, utilizing different mechanisms for energy expression.

The unceasing complexity of life's accumulations has created a great
principle for energy expression--it is termed sublimation--and in popular
parlance represents the spiritual striving of mankind towards the
perfecting of a relation with the world of reality--the environment--which
shall mean human happiness in its truest sense. One of the products of
this sublimation tendency is called Mysticism. This work would seek to aid
us to an understanding of this manifestation of human conduct as expressed
in concrete or contemplated action through thought. It does so by the
comparative method, and it is for this reason I have been led to present
it to an English reading public.

Much of the strange and outre, as well as the commonplace, in human
activity conceals energy transformations of inesti