Introduction 3 



ing. The book used in classes or reading circles 

 does not presuppose a teacher who is already 

 familiar with the subject-matter, merely one 

 who is willing to re-read and think until the 

 matter becomes reasonably clear. It is sug- 

 gested that after reading each chapter individu- 

 ally the group should come together to discuss 

 the content. The appended list of books wUl 

 be an aid to those who wish to read more widely 

 on the topics presented or who wish to prepare 

 reports for the class on particularly interesting 

 phases of the subject. 



