This book is a selected collection of letters of, to and about Meghnad Saha and his writings to commemorate his 125th birth anniversary, supplemented by an overview of him as a scientist, social worker, activist, organizer, father and family man. The letters convey the huge impact of Meghnad Saha’s scientific contributions, the respect that he commanded among his peers, his persona and undaunted spirit, and a sense of time that should be of great interest and also inspirational to the modern readers. Some of the letters contain Meghnad Saha’s own narrative of the development of his famous contribution to astrophysics, the Saha Equation, and his struggles to find very modest financial resource to support his research and publications and how he got deprived of the credit for another landmark discovery of Selective Radiation Pressure. There is also a valuable collection of pictures showing Meghnad Saha with many of the stalwarts in the field of physics and astrophysics in the 20th century, many of whom he invited to India, political leaders of India, his family members and academic colleagues, and in his organizational activities. A final section contains brief summaries of the careers and scientific contributions of the letter writers.Foreword .... vii Preface .... ix Acknowledgments .... xvii 1. Brief Biographical Sketch .... 1 2. Life with Father: Chitra Roy .... 3 3. A Collection of Pictures .... 17 4. Letters: Western Scientists .... 43 4.1 Russell Letters: 1921–1945 ..... 43 4.1a Between Russell and Saha ..... 43 4.1b Between Russell and Other Western Scientists on Saha ..... 66 4.2. Between Arnold Sommerfeld and Saha: (1921-1936) ..... 85 4.3 From Wilhelm Westphal: 1921-1922 ..... 90 4.4 From Alfred Fowler: 1921 ..... 93 4.5 From Ralph H. Fowler: 1923-37 ..... 94 4.6 From Robert A. Millikan: 1924 ..... 96 4.7 Between Marcel Minnaert and Saha: 1955 ..... 97 4.8 From Erich Regener: 1934 ..... 100 4.9 From Arthur S. Eddington: 1934-1937 ..... 101 4.10 From Edward A. Milne: 1935 ..... 104 4.11 Between Harlow Shapley and Saha: 1935-1953 ..... 106 4.12 From Arthur Holly Compton: 1936-1937 ..... 114 4.13 From Rudolf Ortvay: 1936 ..... 116 4.14 Between Niels Bohr and Saha: 1936–1946 ..... 117 4.15 From Erwin Schrödinger: 1936 ..... 122 4.16 From Ernest Rutherford: 1936 ..... 126 4.17 Between Paul Dirac and Saha: 1936–1954 ..... 128 4.18 From Max Born: 1936–1948 ..... 130 4.19 Between Harry Plaskett and Saha: 1946-1947 ..... 134 4.20 Between Edward Appleton and Saha: 1948 ..... 147 4.21 From Saha to Patrick Blackett: 1948 ..... 149 4.22 From Saha to John E. Lennard-Jones: 1949 ..... 150 4.23 From Saha to Irène Joliot-Curie: 1949 ..... 151 4.24 Between Leslie A. White and Saha: 1954 ..... 154 4.25 From Saha to Felix Bloch: 1954 ..... 156 5. Letters: Indian Scientists and Administrators .... 157 5.1 Between Asutosh Mookerjee and Saha: 1921–1922 ..... 157 5.2 Between Prafulla Chandra Ray and Saha: 1921–1935 ..... 163 5.3 From Jnan Chandra Ghosh: 1921 ..... 167 5.4 Between Satyendra Nath Bose and Saha: 1921 ..... 168 5.5 From Snehamoy Dutta: 1922 ..... 171 5.6 From Subrahmanyan Chandrasekhar: 1935 ..... 173 5.7 Between Homi Jehangir Bhabha and Saha: 1947 ..... 178 5.8 From Father to Son (Ajit K. Saha) ..... 182 5.9 From Saha to J.W. Whitaker: 1953 ..... 183 6. Miscellaneous Letters .... 185 6.1 From Asutosh Mookerjee: 1920 ..... 185 6.2 From Kathe Schmidt: 1921 ..... 187 6.3 From Albert Einstein: 1922 ..... 188 6.4 From Margot Milne to Mrs. Saha: 1935 ..... 190 6.5 From R. Ortvay: 1936 ..... 191 6.6 From Arnold Sommerfeld: 1936 ..... 193 6.7 From Rabindranath Thakur (Tagore): 1938 ..... 194 6.8 From Saha To Nehru: 1954 ..... 196 7. Saha’s Writings on Scientists and Other Issues .... 197 7.1 A Chapter of History: The Case of the Missing Scientist ..... 197 7.2 Albert Einstein (1879–1955) ..... 199 7.3 Sir Jagadis Chandra Bose (1858-1937) ..... 214 7.4 Sir Prafulla Chandra Ray ..... 220 7.5 Scientific Reminiscences — C.V. Raman ..... 223 7.6 The Proposals for an Indian Academy of Science ..... 226 8. Scientists in the Letters: Brief Notes .... 233 8.1 Western Scientists ..... 233 8.2 Indian Scientists