The electron microscope was conceived and built in the Technical University of Berlin some 50 years ago. Much of its further development took place in university laboratories. Not entirely fortuitously, some significant contributions came to be made in the Cavendish, in respect of high voltage operation and the improvement of resolution, and in microanalytical instrumentation. The story of this involvement, and the vicissitudes it underwent, throws light on the way conceptions become dised in practice and on the interrelations of academic research and industrial innovation.