Includes correspondence with George Baldwin, C. F. Barnett, G.A. Bell, David C. Cartwright, Professor C.G. Cavalleri, Dr Cohen (Institute of Physics), Basil Day, Ron Ewer, Dr Ian Fleming, Dr D.E. Golden, Mr. Havelock (Schlank and Co), J.C. Kelly (Institute of Physics NSW), W.R.G. Kemp, Derek F. Klemperer, Professor J. William McGowan, J.D. Mellor, Ralph W. Parsons (Institute of Physics Queensland), Dave C. Peaslee, Dr Pollard (Institute of Physics NSW), Professor Dr H. Raether, Ralph (Wayne State University), Dr J.C. Riviere (United Kingdom Atomic Energy Authority), Beatrice Shube, W.H. Sutherland, Dr K Tachibana, A.M. Thompson, R.F. Whitmer, Frank Wood (Australian Institute of Physics), and Professor A. von Engel.