U ACKNOWLEDGMENTS 



J^ This work was made possible through the generosity of Professor R. A. 

 Dart, Dr. and Mrs. L. S. B. Leakey, Dr. G. H. R. von Koenigswald, Dr. D. 

 Hooijer, and Dr. J. T. Wiebes. 



I express my thanks to Miss C. J. Orkin, Mrs. J. Asch, Mrs. E. Judd, 

 and Mrs. E. Hibbett, for their painstaking preparation of the manuscript; 

 to Mr. A. R. Hughes, Mr. B. Hume, and Mr. M. Hockman, for preparation 

 of the illustrations; and to Mr. R. J. Clarke, Mr. C. Block, and Miss S. Etoe 

 for other assistance. 



The original researches reported in this volume were subvented by the 

 Research Committee of the University of the Witwatersrand, the Council 

 for Scientific and Industrial Research of South Africa, the Wenner-Gren 

 Foundation for Anthropological Research, the National Science Foundation, 

 and the Boise Fund. 



I am indebted to Dr. Harry L. Shapiro for kindly writing the Foreword, 

 to the American Museum of Natural History for according me the honor 

 of inviting me to deliver the thirty-eighth James Arthur Lecture; and 

 especially to Dr. Shapiro and Dr. Lester R. Aronson for their kindness and 

 assistance. 



Finally, I sincerely appreciate the patient and friendly cooperation of 

 those many people at the Columbia University Press— and particularly the 

 editor, Mrs. E^rbara-Jo Kawash— who have collaborated superbly in pro- 

 ducing this little book. It has been a pleasure to work with them. 



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