student age.  I have undertaken the task with great gladness because my
long and happy contact with men and women through the Student Movement
has taught me how great is the need for a fuller understanding of the
problems of sex, and how possible it is that men and women should find
help through the timely suggestion of right and wholesome thoughts. 

My brother, Dr.  Charles Gray of London, has contributed a very valuable
appendix dealing with certain facts in a way which is only possible to
a medical man, and I am very greatly indebted to him for thus enriching
this volume. 

It will be apparent to all who read it that I also owe a great deal to
many who have shared with me their knowledge and experience.  In
particular I owe much gratitude to a number of generous-hearted women
who have enabled me to write the chapters which are more especially
addressed to their sex. 

I have deliberately omitted from these pages any reference to disease.
I do that not because I am not impressed by the terrible penalties with
which nature visits certain sins, but because I do not believe in the