PREFACE 



to express our gratitude to the publishers whose kindness and co-operation were 

 such that all our {i.e. the Authors' and the Editor's) wishes were taken into 

 consideration (though some of them were far from simple!). 



Finally, I would like to thank my former secretary Mrs. Leedia Greve Hanrahan 

 and my present secretary, Mrs. Dorothy Rohde, who contributed so effectively 

 towards making the task of the Editor much easier. 



January ig6o Wiktor W. Nowinski 



