When retired it is a blessing if one has not become too tired by the strain of one's professional career. In the case of our retired engineer and scientist Rinus Vlaardingerbroek, however, this is not only a blessing for him person ally, but also a blessing for us in the field of Magnetic Resonance Imaging as he has chosen the theory of MRI to be the work-out exercise to keep himself in intellectual top condition. An exercise which has worked out very well and which has resulted in the consolidated and accessible form of the work of reference now in front of you. This work has become all the...