PREFACE 



the study. Among others, my History of Creation 

 (EngHsh translation) and Evolution of Man (EngUsh 

 translation now in course of preparation) will be 

 found helpful in this way. The German reader will 

 also find many illustrations to elucidate the text of 

 this book in my recently completed work, Kiinst- 

 f or men der Natur (lo parts, with loo tables, 1899- 

 1904). 



I had said, in the preface to The Riddle of the Universe 

 in 1899, that I proposed to close my study of the monistic 

 system with that work, and that " I am wholly a child of 

 the nineteenth century, and with its close I draw the 

 line under my Hfe's work." If I now seem to run 

 counter to this observation, I beg the reader to consider 

 that this work on the wonders of life is a necessary 

 supplement to the widely circulated Riddle of the Uni- 

 verse, and that I felt bound to write it in response to the 

 inquiries of so many of my readers. In this second 

 work, as in the earlier one, I make no pretension to give 

 the reader a comprehensive statement of my monistic 

 philosophy in the full maturity it has reached — for me 

 personally, at least — at the close of the nineteenth 

 century. A subjective theory of the world such as this 

 can, naturally, never hope to have a complete objective 

 validity. My knowledge is incomplete, like that of all 

 other men. Hence, even in this "biological sketch-book," 

 I can only offer studies of unequal value and incomplete 

 workmanship. There still remains the great design of 

 embracing all the exuberant phenomena of organic 

 life in one general scheme and explaining all the 

 wonders of life from the monistic point of view, as 

 forms of one great harmoniously working universe — 

 whether you call this Nature or Cosmos, World or 

 God. 



The twenty chapters of The Wonders of Life were 

 written uninterruptedly in the course of four months 



ix 



