This book represents in substance a course of lectures and discussions
given first at the University of Illinois and later at Wesleyan
University. It was written to meet the needs both of the college
student who has the added guidance of an instructor, and of the
generalreader who has no such assistance. The attempt has been
made to keep the presentation simple and clear enough to need no
interpreter, and by the list of readings appended to each chapter,
to make a self directed further study of any point easy and alluring.
These references are for the most part to books in English, easily
accessible, and both intelligible and interesting to the ordinary
untrained reader or undergraduate. Some articles from the popular
reviews have been included, which, if not always authoritative,
are interesting and suggestive.

The function of the instructor who should use this as a textbook would
consist, first, in making sure that the text was thoroughly read and
understood; secondly, in raising doubts, suggesting opposing views,
conducting a discussion with the object of making the student think
for himself; and, thirdly, in adding new material and illustration
and directing the outside readings which should supplement this
purposely brief and summary treatment. The books to which reference
is made in the lists of readings, and other books approved by the
instructor, should be kept upon reserved shelves for the constant
use of the class in the further study of questions suggested by
the text or raised in the classroom.

It will be noticed that the disputes and the technical language of
theorists have been throughout so far as possible avoided. The
discussion of historical theories and isms' is unnecessarily
bewildering to the beginner; and the aim has been rather to keep as