Ernest Crawley 
Revival: The Mystic Rose (1960) [EPUB ebook] 
A Study of Primative Marriage and of Primitive Thought in Its Bearing on Marriage

All study of the origins of social institutions must be based on what ethnology can tell us of the psychology of the lower races and on the primitive conceptions of human relations which are thus established. It is only in early modes of thought that we can find the explanation of ceremonies and systems which originated in primitive society; and, if ceremony and system are the concrete forms in which human relations are expressed, an examination, ethnological and psychological, of human relations, is indispensable for enquiry into human institutions.