Man-woman relationships 21 History 7 Social life and customs 5 Criminal behavior 4 Investigation 4 Love triangles 4 Murder 4 mer ... Social conditions 4 Triangles (Interpersonal relations) 4 Campaigns 3 Conduct of life 3 Families 3 High school students 3 Human-alien encounters 3 Interplanetary voyages 3 Interstellar travel 3 Life on other planets 3 Manners and customs 3 Motion picture actors and actresses 3 Revenge 3 Teacher-student relationships 3 Teenage girls 3 World War, 1939-1945 3 Alcoholism 2 Boarding schools 2 Boxing 2 College teachers 2 Criminals 2 Fathers and daughters 2 Fighter pilots 2 mindre ...