and precision which at many points had never been expended before on these
questions. But when we reach the relationships of sex to society we have
for the most part no such neglect to encounter. The subject of every
chapter in the present volume could easily form, and often has formed, the
topic of a volume, and the literature of many of these subjects is already
extremely voluminous. It must therefore be our main object here not to
accumulate details but to place each subject by turn, as clearly and
succinctly as may be, in relation to those fundamental principles of
sexual psychology which--so far as the data at present admit--have been
set forth in the preceding volumes.

It may seem to some, indeed, that in this exposition I should have
confined myself to the present, and not included so wide a sweep of the
course of human history and the traditions of the race. It may especially
seem that I have laid too great a stress on the influence of Christianity
in moulding sexual ideals and establishing sexual institutions. That, I am
convinced, is an error. It is because it is so frequently made that the
movements of progress among us--movements that can never at any period of
social history cease--are by many so seriously misunderstood. We cannot
escape from our traditions. There never has been, and never can be, any
"age of reason." The most ardent co-called "free-thinker," who casts aside
as he imagines the authority of the Christian past, is still held by that
past. If its traditions are not absolutely in his blood, they are
ingrained in the texture of all the social institutions into which he was
born and they affect even his modes of thinking. The latest modifications
of our institutions are inevitably influenced by the past form of those
institutions. We cannot realize where we are, nor whither we are moving,
unless we know whence we came. We cannot understand the significance of
the changes around us, nor face them with cheerful confidence, unless we
are acquainted with the drift of the great movements that stir all