iv Contributing Editors 



K. Mendelssohn, D.Phil. 



Clarendon Laboratory, Oxford 



G. J. Neary, M.A., Ph.D. 



Physics Department, Mount Vernon Hospital and the Radium Insti- 

 tute, Northwood, Middlesex 



J. Read, B.Sc, Ph.D. 



Physicist, Radiotherapy Department of the London Hospital 



S. Russ, C.B.E., D. Sc. 



Professor of Physics in the University of London, Physicist to the 

 Middlesex Hospital 



F. G. Spear, M.A., M.D., D.M.R.E. 



Strangeways Research Laboratory, Cambridge and Member of the 

 Scientific Staff, Medical Research Council 



