The 20th century can truly be called the Century of Space Science', for it was in the 20th century that the multidisciplinary study of space science (as opposed to astronomy) was conceived. Today, as we start a new century of discovery, we are able to cast our perspective back in order to chronicle how the field began, review how it developed, and discuss how it reached its current levels. We are able to overview the historical development and to put early discoveries in context, to document our current understanding and to look forward to the coming century with some degree of optimism. One of the most attractive features of this young discipline is that many of the original pioneers and key players involved are still available to describe their field. Hence, at this point in history we are in a unique position to gain first hand insight into the field and its development. To this end, The Century of Space Science, a scholarly, authoritative, reference book presents a chapter by chapter retrospective of space science as studied in the 20th century. The level is academic and focuses on key discoveries, how these were arrived at, their scientific consequences and how these discoveries advanced the thoughts of the key players involved. With over 90 world class contributors, such as James Van Allen, Cornelis de Jager, Eugene Parker, Reimar L st, and Ernst Stuhlinger, and with a Foreword by Lodewijk Woltjer (past ESO Director General), this book will be immensely useful to readers in the fields of space science, astronomy, and the history of science. Both academic institutions and researchers will find that this major reference work makes an invaluable addition to their collection. The work is published in two large format volumes and contains colour images throughout. It includes several appendices (for example a basic chronology of the field and a complete list of every space science mission ever launched) and is extensively and comprehensively indexed. The scientific editorial team consists of Johan A.M. Bleeker (of SRON, Netherlands), Johannes Geiss (of the International Space Science Institute, Berne) and Martin Huber (of ESA) and history consultant Arturo Russo (of the University of Palermo, Italy).