Dr. Ramaswamy Jagannathan retired as a Professor of Physics from The Institute of Mathematical Sciences, Chennai, India (Email: jagan@imsc.res.in). His research interests are, in general, in Theoretical and Mathematical Physics. He has recently written a book, with Dr. Sameen Ahmed Khan (Dhofar University, Oman): "Quantum Mechanics of Charged Particle Beam Optics: Understanding Devices from Electron Microscopes to Particle Accelerators" (Taylor & Francis , 2019).