

PREFACE. 



The contents of this volume consist of the 

 first ten lectures of the thirty-five in the Win- 

 ter course of 1907-08. They were delivered in 

 the Garrick Theater, Chicago, on Sunday morn- 

 ings to crowded houses. On several occasions 

 half as many people were turned away as 

 managed to get in. If these lectures meet with 

 as warm a reception when read as they did 

 when heard, I shall be more than satisfied. For 

 a fuller discussion of the Greek period, briefly 

 dealt with in the first lecture, see Edward 

 Clodd's *Tioneers of Evolution'^ to which work 

 the early part of this lecture is greatly indebted. 



Every lecture proceeds on the assumption, 

 that a knowledge of the natural sciences, and 

 especially the great revolutionizing generaliza- 

 tions which they have revealed, is indispens- 

 able to a modern education. 



This position is by no means new. It per- 

 vades the classic literature of Socialism 

 throughout. Liebknecht, speaking of Marx 

 and himself says: "Soon we were on the field 

 of Natural Science, and Marx ridiculed the 

 victorious reaction in Europe that fancied it 

 had smothered the revolution and did not 



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