The Development of the Electron and of Electron Microscopy

A month ago, the Nobel Foundation sent me its yearbook of 1985. From it I learnt that many Nobel lectures are downright scientific lectures, interspersed with curves, synoptic tables and quotations. I am somewhat reluctant to give here such a lecture on something that can be looked up in any modern schoolbook on physics. I will therefore not so much report here on physical and technical details and their connections but rather on human experiences--some joyful events and many disappointments which had not been spared me and my colleagues on our way to the finat breakthrough. This is not meant to be a complaint though; I rather feel that such experiences of scientists in quest of new approaches are absolutely understandable, or even normal. In such a representation I must, of course, consider the influence of my environment, in particular of my family. There have already been some scientists in my family: my father, Julius Ruska, was a historian of sciences in Heidelberg and Berlin; my uncle, Max Wolf, astronomer in Heidelberg; his assistant, a former pupil of my father and my godfather, August Kopff, Director of the Institute for astronomical calculation of the former Friedrich-Wilhelm University in Berlin. A cousin of my mother, Alfred Hoche, was Professor of Psychiatry in Freiburg/Breisgau; my grandfather from my mother's side, Adalbert Merx, theologian in Giessen and Heidelberg. My parents lived in Heidelberg and had seven children. I was the fifth, my brother HeImut the sixth. To him I had particularly close and friendly relations as long as I can remember. Early, optical instruments made a strong impression on us. Several times Uncle Max had shown us his telescopes at the observatory on the K6nigstuhl near