PREFACE 



THE publication of the present work on The Won- 

 ders of Life has been occasioned by the success of 

 The Riddle of the Universe, which I wrote five years 

 ago. Within a few months of the issue of this study 

 of the monistic philosophy, in the autumn of 1899, ten 

 thousand copies were sold. Moreover, the publisher 

 having been solicited on many sides to issue a popular 

 edition of the work, more than a hundred thousand 

 copies of this were sold within a year.' This extraor- 

 dinary and-— as far as I was concerned — unexpected 

 success of a philosophical work which was by no means 

 light reading, and which had no particular charm of 

 presentation, affords ample proof of the intense interest 

 taken by even the general reader in the object of the 

 work — the construction of a rational and solid philos- 

 ophy of life. 



Naturally, the clear opposition of my monistic philos- 

 ophy, based as it was on the most advanced and sound 

 scientific knowledge, to the conventional ideas and to an 

 outworn "revelation," led to the publication of a vast 

 number of criticisms and attacks. During the first twelve 

 months more than a hundred reviews and a dozen large 

 pamphlets appeared, full of the most contradictory 

 strictures and the most curious observations. One of 



' The English translation met with almost equal success. 

 Nearly one hundred thousand copies of the cheap edition have 

 already been sold. — Trans. 



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