The first radio links, wireless telegraphy, were established at the beginnings of the twentieth century by Marconi, who drew upon the theory developed by Maxwell and upon the experimental researches conducted by Hertz. In France, such renown scientists, mathematicians, physicists and experimenters as Poincaré, Blondel and the Général Ferrié played a crucial role in the development of radiocommunications, more particularly through theoretical and experimental researches which contributed to a better understanding of the different propagation media. Following the Second World War, the researchers and engineers of the newly created Centre National d Etudes des Télécommunications (CNET), among whom may be mentioned Jean Voge, François du Castel, André Spizzichino or Lucien Boithias, made decisive contributions to the understanding of the propagation of radio waves, in particular in the context of their application to telecommunications. Although the CNET has now become France Telecom Recherche & Développement, the present book is in keeping with this approach, which has been going on for more than half a century. By providing the reader with some of the most recent researches in this field, Hervé Sizun offers here an essential complement to the work by Lucien Boithias Radiowave Propagation, first published in 1983 in the Collection Technique et Scientifique des Télécommunications, and published in an English version in 1987 by McGraw- Hill.