Wrong teachings about sex--Children brought up in ignorance on sex matters--No information given by parents, schools, churches--But children will find out even if they go to wrong sources--Some one must tell the truth--This book does it. THE ARGUMENT AND THE INFORMATION Until recently it was a crime to give knowledge concerning sex relations--Sex knowledge denied through selfishness or prudery--This is wrong because sex is of highest importance to human beings--Ills, crimes, misfortunes are result when people are forced to be ignorant of knowledge they need--Condemned to suffer tortures when they might enjoy delights--Sex is clean and natural--At last sex knowledge may be given freely--Advice in this book gained from personal and professional experience. THE CORRECT MENTAL ATTITUDE Definite information now given which will help husbands and wives to find perpetual and increasing happiness all their lives--Duty of brides and grooms to acquaint themselves with each other's sexual needs--No man or woman should be ashamed of the sexual make-up--They should be proud of their sexual functions and virility--Read the book without shame or shock--Gaining honest truth about these matters is most essential to life. THE SEX ORGANS Male sex organs are penis and testicles--Size and form of penis when at rest and during sexual excitement--Position of testicles--Why one teste is larger--Pubic regions in men and women. Female sex organs are vulva, vaginal passage, womb, and ovaries--Length of vaginal passage compared with distended penis--Size and formation of womb--Position of ovaries. FUNCTION OF THE SEX ORGANS Primary purpose of sex in the human race--Life is the result of union of two forces--Birth the same in human beings as in other forms of life--Process of conception in female--How female ovum is fertilized by male--When puberty begins and ends in women. Menstruation, its cause and meaning--When ovum may be impregnated--Origin of sperm in man--Purpose of prostate gland--What semen is--For birth of new life union of male and female sex organs necessary--Glans penis in man and clitoris in woman are "exciting" focal points--Climax of coitus. Use of sexual organs to produce offspring same in mankind as in animals--One way in which human beings differ from animals in sex relations--Coitus possible in animals only in "rutting" season--In human beings coitus enjoyable at any time--What this difference means to happiness--The basis of real success in marriage--Married people can reach highest conditions of wedlock when they know and practice what is right in sex--No "rights" conferred in sex relations through the ceremony of marriage.