PREFACE 



Tlie object of tliis book is to prosont in oloiiiciitary 

 form a summary of the most generally accepted evidence 

 and theory of Social P^volution. It does not pretend to 

 he an intensive treatise or to advance any untested 

 doctrine. The writer believes that there is a definite 

 lilace to be filled by a book which, as a text for the study 

 of Sociology, applies the best of sociological and evolu- 

 tionary theory to the historical study of society. With 

 the increasing emphasis that historians are placing upon 

 social and economic phenomena, the average student 

 learns at least something of the importance of social 

 forces. At the present time the vast period of Iniinaii 

 evolution before the historical period, is known to us 

 only l)y the matei'ial ))resent(Ml in highly specialize*! 

 works. There is no single elementary presentation of 

 t he increasing body of scientific knowledge which enables 

 us to picture prehistoric conditions. The author believes 

 that the study of history and social science is made more 

 real and valuable by some familiarity with the conditions 

 and factors which were important in this early period. 



Professor W. I. Thomas says : " It is of course entirely 

 proper for the student to limit himself very narrowly to 

 a special field in order to work it intensively, but the his- 

 torian, for instance, wlio begins the study of human 

 activity with Greece and Pome or even with Assyria and 

 Figypt, cuts himself off completely from the beginnings of 

 his own subject as would the psychologist who neglected 



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