EDITOR'S PREFACE 



At the time of the Symposium the undersigned were given the task 

 of editing for publication the presented papers, formal discussions, and 

 comments from the floor. The latter, of course, posed the most serious 

 problems, and we elected to handle them in the following manner: Each 

 of us took rather complete notes and at the end of each half-day session 

 these were used to select those remarks which we felt should be given in 

 the exact words of the speaker and they were then asked to write out or 

 dictate their remarks. Short questions, answers, or statements which 

 seemed completely clear have been taken from our notes. For a number 

 of these, however, the content was checked with the originator during 

 informal discussions. 



We wish to thank all of the participants for the splendid coopera- 

 tion given us in compiling the informal discussions and we hope that in 

 the process of editing and compiling we have not done injustice to any of 

 their statements. 



The papers and the formal discussions presented after each of them, 

 have been edited as little as was consistent with the problems of printing, 

 referencing, etc. Some consideration was given to rationalizing the various 

 notations but this seemed unnecessary and unwise. Although we went 

 over all of the papers jointly, most of the editing for the first half was 

 ' done by Dr. Press and most of the editing for the second half by Dr. Wilson. 

 The manuscripts came to us in good order and for this we wish to thank 

 the authors. 



Finally we wish to express our appreciation to Dr. R. C. Gibbs who 

 has handled many of the problems and details that would normally have 

 fallen to us. 



James T. Wilson 

 Frank Press 



