Preface

This book grew out of a personal need to carry out my work more efficiently. It was in the 60s when I began to develop the first highly structured air shower simulation program and was carrying out extensive air shower simulations on an almost industrial basis. The primary aim at that time was to study the systematics of hadronic interactions at the highest energies in conjunction with experimental air shower and accelerator data. This goal remains to date but today the determination of the primary mass, its energy dependence and questions related to the origin, acceleration and propagation of the most energetic cosmic rays are in the foreground. The results obtained with the ever growing shower model that eventually grew into the program system named ASICO (Air shower SImulation and COrrelation), which later on became CORSIKA, were so manifold and rich, and covered essentially the full scope of air shower observables that it became necessary to build a library of experimental data for comparison and efficient analysis work; this was the beginning of this book. As the library grew it became evident that it could be of interest to a broader community, active in air shower research. A natural consequence was to add theoretical and tutorial sections to the various chapters, and to expand the book to a comprehensive reference manual for researchers that can also be used as a text book for the advanced student. The data presented in these two volumes are not an all-inclusive collection. In view of the very large number of experiments that were carried out by so many research groups throughout the years it became unavoidable to take a selection for the presentation here, to compile the data and summarize results. Emphasis was therefore given to the historically as well as the contemporarily scientifically relevant information and data. The fast evolving field of ground based high energy gamma ray astronomy, which employs air shower detection techniques (air Cherenkov as well as particle detection), is only touched on the side, mostly in connection with wide-angle large aperture atmospheric Cherenkov detector arrays. Today, the field of gamma ray astronomy is essentially a separate discipline of its own, yet it remains closely related to cosmic ray and air shower research.