On 29 September 2003, La Sapienza University of Rome bestowed the laurea degree honoris causa in electronic engineering on Prof. Arthur A. Oliner for pioneering contributions to the theory of guidance and radiation of electromagnetic waves. Prof. Oliner has been an outstanding personality in the electromagnetics world for more than 50 years. He has been one of the principal leaders of the great development of the theory and the applications of microwaves that occurred during the years soon after WWII. Prof. Oliner has carried out his scientific and teaching activity at the Polytechnic Institute of Brooklyn, now Polytechnic University, where he is currently Emeritus Professor. At the same time, however, he has visited many universities all over the world, including many visits to La Sapienza University of Rome. He obtained many memorable results in the various fields of electromagnetic theory and applications: it is enough to recall his innovative research on guided propagation, radiation phenomena, and methods of circuit representation. For such studies, and for his brilliant teaching, he has received numerous awards and international recognition. Also of particular relevance are his reflections and his contributions as a witness to the history of scientific events in the field of electromagnetics over the last half century. For the many of us who know and admire Prof. Oliner, this was a wonderful opportunity to celebrate him and his work. What follows is the lecture he presented on this occasion.