VI PREFACE 



The effects of the three types of radiation are presented in three vol- 

 umes: Vokime I, ionizing (high-energy) radiations ; Vohime II, ultraviolet; 

 and Volume III, visible light. Since many biological effects are common 

 to both ionizing and ultraviolet radiation, a sharp separation of these 

 fields is no longer possible. The first two volumes might, therefore, be 

 regarded as a whole. Both the ultraviolet and high-energy regions of the 

 spectrum are discussed in individual chapters in both volumes. The 

 radiation biology field, in general, is so active that, although only two 

 years have elapsed since initiation of these publications, some of the dis- 

 cussions are not up to date. Space does not permit inclusion of all sub- 

 jects of interest to the radiation biologists; some worthy topics are omitted 

 for lack of an appreciable amount of new material. Studies on the use of 

 radioisotopes as a research tool are not included because adequate texts 

 are already available. 



Gratitude is expressed to Dr. R. E. Cleland, who, during his tenure as 

 chairman of the Division of Biology and Agriculture of the National 

 Research Council, gave encouragement in the planning of these volumes; 

 to Dr. Paul Weiss, the present chairman, who added his ready support to 

 the project; and to the other members of the National Research Council. 

 Acknowledgment is also made of the contribution of the members of the 

 editorial boards of the separate volumes of "Radiation Biology." With- 

 out the generous support of the Division of Biology and Medicine of the 

 Atomic Energy Commission and the Oak Ridge National Laboratory, the 

 preparation of this work would not have been possible. 



Alexander Hollaender, Editor 



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