In these Essays—little, indeed, as I know them to be, compared to the magnitude of their subjects—I have tried to set forth, as clearly as I can, certain fundamental principles, together with their practical application to the life of our time. Some of these principles were stated, more briefly and technically, in my larger Studies of sex; others were therein implied but only to be read between the lines. Here I have expressed them in simple language and with some detail. It is my hope that in this way they may more surely come into the hands of young people, youths and girls at the period of adolescence, who have been present to my thoughts in all the studies I have written of sex because I was myself of that age when I first vaguely planned them. I would prefer to leave to their judgment the question as to whether this book is suitable to be placed in the hands of older people.