It is a century since one of the icons of modern physics submitted some of the most influential scientific papers of all times in a few months; and it is fifty years since he died. There is no question that Albert Einstein with his work on relativity and quantum theory has marked the development of physics indelibly. To reappraise his lifework forces one to rethink the whole of physics, before and after him.

The aim of the present book is to contribute to this daunting task. Though not an encyclopedic work, it tries to provide a perspective on the history of physics from the late 19th century to today, by taking the series of groundbreaking and sometimes provocative contributions by Einstein as the demarcation line between the “old” and the “new” physics. The treatment is not meant as celebratory, but to provide accurate information (both historical and conceptual) and critical appraisal.

Since it is clearly impossible to deal within a relatively small compass with all the topics which would have been suitable for special treatment, a choice – sometimes a painful one – had to be made. It would be wanton to assume that all readers should find the selection presented here as ideal; however the editor is confident that it is neither so arbitrary nor so conventional as to seriously detract from the interest of the whole.

Although this book has been inspired by an historical occasion (a double one, in fact), it is not an occasional one. The authors have a long record of working on themes related to Einstein or Einstein's work and its consequences. What they have to say should be of interest to a wide range of scholars and students in physics, history of science, and epistemology.

However, this is not a book for specialists only. An effort has been made to make the bulk of the book understandable to lay persons with some knowledge of undergraduate mathematics and physics. Most parts of physics can surrender a considerable part of their cultural import to any non-specialist seriously intentioned to grasp the main concepts. The authors have tried to avoid unnecessary technical jargon and to paraphrase in words the main formulas, though some sections or chapters may turn out to be more hard going than others. However, it is a fact that Einstein's work has been instrumental in introducing a previously unheard-of degree of mathematical sophistication into theoretical physics. Ninety years after the event it would be a deceptive simplicity that achieved at the cost of concealing this crucial aspect.

In closing this preface, the editor is very pleased to thank Dr. Einar H. Fredriksson, of IOS Press, for his constant interest and encouragement, and to acknowledge the care and forbearance of Anne Marie de Rover and the other staff of IOS Press.

Marco Mamone Capria, mamone@dipmat.unipg.it, March 2005