X Preface 



on wheat and maize production. In this study we developed our 

 basic approach to international diffusion of "knowledge." Chapter 

 5 reports an extension in the direction of utilizing more aggregate 

 data. The chapter reports on aggregate analysis of agricultural pro- 

 ductivity in thirty-six countries. Data on all factors of production 

 are incorporated. 



Chapter 6 analyzes productivity change in Indian agriculture. 

 The Indian experience provides an excellent testing ground for 

 the empirical models that have been developed for international 

 comparisons. If the relationships between research activity and 

 productivity can be shown to hold for productivity in India, we 

 have a strong basis for claiming to have identified a general rela- 

 tionship. The Indian data also make possible an estimate of the 

 contribution of extension programs to productivity. 



Chapters 7 and 8 turn to theoretical specifications of tech- 

 nological discovery and diffusion. Chapter 9 provides a summary 

 of the economic and policy implications of the book. 



This study is mainly devoted to an attempt to explain the role of 

 scientific research in increasing agricultural productivity. The so- 

 called second generation problems of the new technologies and 

 their socioeconomic consequences are not treated here at all, but 

 the reader should bear their existence in mind. 



Our work gave rise to a host of issues and problems. Not all of 

 them could be solved and we hope that raising these issues and 

 discovering the shortcomings of our knowledge will encourage 

 more complete coverage of data by statistical agencies, and 

 further studies of these subjects. 



Much, though not all, of the substantive content of the volume 

 has been discussed in other publications. We have added signifi- 

 cant new material to the original studies and redrafted the presen- 

 tation for this volume. Acknowledgment of related publications is 

 made in the footnotes. 



Support for the research on which this volume is based was 

 provided by the Economic Growth Center of Yale University, the 

 International Bank for Reconstruction and Development, and the 

 National Science Foundation (GS-36863). 



