XX PREFACE 



PREFACE TO THIRD EDITION 



In this, the third edition, certain anthropological ma- 

 terial has been brought up to date. 



F. S. C. 

 December, 1916. 



PREFACE TO FOURTH EDITION 



Social evolution proceeds by social selection as well as 

 by natural selection. More adequate treatment of the selec- 

 tive processes in society than appeared in Chapter IV of 

 earlier editions of this book is given in Appendix I. For 

 permission to print this material from his paper, "Primitive 

 Social Ascendancy Viewed as an Agent of Selection in 

 Society" in the Proceedings of the American Sociological 

 Society, 1917, the author is indebted to the editors. 



F. S. C. 



July, 1919. 



