there will be results in which all the so-called
"supernatural, spiritual, psychic" phenomena, such as are not fakes, will
become scientifically understood and will be consciously utilized. Now
they are mostly wasted or only played with. It may happen that the science
of Man--as the science of time-binding--will disclose to us the inner and
final secrets--the final truth--of nature, valid in infinity.

It is very difficult to give in such a book as this an adequate list of
the literature which may help to orient the reader in a general way in the
great advance science has made in the last few years. This book is a
pioneer book in its own way, and so there are no books dealing directly
with its subject. There are two branches of science and one art which are
fundamental for the further development of the subject; these two sciences
are (1) Mathematical philosophy and (2) Scientific biology, the art is the
art of creative engineering.

In mathematical philosophy there are to my knowledge only four great
mathematical writers who treat the subject as a distinct science. They are
two English scientists, Bertrand Russell and A. N. Whitehead; one
Frenchman, Henri Poincare (deceased); and one American, Professor C. J.
Keyser. Messrs. Russell and Whitehead approach the problems from a purely
logical point of view and therein lies the peculiar value of their work.
Henri Poincare was a physicist (as well as a mathematician) and,
therefore, approaches the problems somewhat from a physicist's point of
view, a circumstance giving his philosophy its particular value. Professor
Keyser approaches the problems from both the logical and the warmly human
points of view; in this is the great human and practical value of his
work.

These four scientists are unique in their respective elaborations and
elucidations of mathematical philosophy. It is not for me to advise the
reader what selections to make, for if a thorough knowledge of the subject
is desired the reader should read all these books, but not all readers are
willing to make that effort toward clear thinking (which in the meantime
will remain of the _highest_ importance in science). Some readers will
wish to select for themselves and to facilitate their selection I will lay
out a "Menu" of this intellectual feast by giving in some cases the
chapter heads.

For many temporary reasons I was not able, before going into print, to
give a fuller list of the writings of those four uniqu