Issues

If Bohr had been a lawyer, if, for some reason, one or more of the great discoveries had not been made, physicists would still have arrived at a complete and consistent quantum theory, stepping on the stones provided by other men's work. A few roads not taken might have made things happen faster than they did.

In efforts to rid quantum electrodynamics of its infinities, there were many false starts. But along the way the author learned many ways of formulating the theory especially with path integrals of actions. A new point of view developed, one of examining an interaction over all space and time rather than its detailed behavior as a function of time. The reformulation succeeded eight years after its enthusiastic beginning.

More than 10 000 physicist are active in West Germany's 28 universities, numerous Max Planck Institutes and industrial laboratories.

With understanding of energy trapping, vibration theory is reducing crystal‐filter design to handbook form. Masers and beam tubes too are enjoying developments giving frequency stabilities of one part in $1014.$