In this book some 50 papers published by K A Mller as author or co-author over a period from 1959 till 2009, amplified by more recent work mainly by T W Kool with collaborators are reproduced. The main subject is Electron Paramagnetic Resonance (EPR) applied to the study of perovskites and other oxides with related subjects. This wealth of papers is organized into eleven chapters, each with an introductory text written in the light of current understanding. The contributions of the first author on structural phase transitions have been immense, and because K A Mller and J C Fayet have published a review paper on the subject, the latter is reproduced in chapter VII. Exceptions is here I have omitted the half sentence on chapter VI, it is EPR related whole chapter VIII on dipolar and quantum paraelectric behavior with dielectric studies. Further in chapter X two papers proving the existence of Fermi-Glasses are reproduced.

The year 1986 bears some significance: early in this year the paper by Bednorz and Mller on the possible observation of superconductivity was published. This resulted in a substantial shift in the paradigm of condensed matter physics to which the present first author has scientifically with those that of others in a second volume.