In the summer of 1970 I attended as a graduate student from MPI Munich the Brandeis Summer School on Theoretical Physics at Brandeis University. Afterwards I drove in a car which I had to deliver eventually in Long Beach, California, throughout the United States. This trip was not only my first encounter with the magnificent sceneries of the United States. On a short stay at the Physics Center in Aspen, Colorado, I met in a discussion with colleagues on problems of broken scale invariance Murray Gell–Mann for the first time.

The year 1970 was an exciting one in particle physics. After several years of frustration and little progress in experimental studies, the observation of the scaling phenomena in inelastic electron–nucleus scattering at SLAC had started a new era in particle physics. I had the hunch, like numerous other theorists, that the “SLAC scaling” might have something to do with scale invariance in field theory, the topic of my Ph. D. – thesis, which had been given to me by Heinrich Mitter at the MPI in Munich. In 1970 Gell–Mann was working, partially together with Peter Carruthers, on the problem of scale invariance and its breaking in hadron physics, a topic, which at a first sight seemed unrelated to the “scaling phenomenon” seen at SLAC. I remember a number of conversations I had with Murray at the Aspen Physics Center, in which we talked about possible connections.