VIU PREFACE 



entails well-known dangers. The Editors dare not hope that they have 

 evaded them, but in designing the book they have, as far as lay in their 

 power, made a determined effort to avoid producing a mere collection of 

 essays or review articles. Instead they have attempted to provide a con- 

 tinuous narrative in which the tale, although taken up by one storyteller 

 after another, nevertheless has a continuous and connecting thread running 

 through it from beginning to end. There may be gaps in the narrative, parts 

 of the story may be told more than once, but a sincere attempt has been 

 made to help the reader by linking the chapters with abundant cross refer- 

 ences. And it must not be forgotten that, even in a book of this size, the 

 story is far from complete, for additions to our knowledge of the nucleic 

 acids are made available with almost every issue of a host of scientific 

 journals. 



The Editors owe a deep debt of gratitude to the many contributors who 

 have made the treatise possible and to the publishers for their unfailing 

 help and advice. They also wish to thank their secretaries, Mrs. Emmy 

 Bloch and Miss Mary Gilmour, for their patient and willing help. 



If this book helps create an early need for a supplement to its present 

 content, it will have fulfilled one of its purposes. 



Erwin Chargaff 

 J. N. Davidson 



