The discovery of radioactivity a century ago opened up a new field in science, that of the atomic nucleus, which culminated 40 years later in the discovery of fission, and its practical consequences in the form of nuclear weapons and nuclear power reactors. That remains still the focus of news media as it influences international politics and national energy policies. However, nuclear science has contributed much more to our daily life as it has penetrated into practically every important area, sometimes in a pioneering way sometimes by providing completely new solutions to old problems: from the history of the universe and our civilisation to methods of food production and to our health from youth to old age. It is a fascinating field continuously developing. Nuclear chemistry is an important part of this.
   The subject of this book has it roots in chemistry and in nuclear science. Since every chemical element can be made radioactive and followed through chemical reactions by means of this property, radiochemistry has contributed to most areas of chemistry. Nuclear chemistry - according to a definition by Ernst Rutherford includes all changes in elemental composition by nuclear reactions.
   We simply define radiochemistry and nuclear chemistry by the content of this book, which is primarily written for chemists. The content contains fundamental chapters followed by those devoted to applications. Each chapter ends with a section of exercises (with answers) and literature references. An historic introduction (Ch.1) leads to chapters on stable isotopes and isotope separation, on unstable isotopes and radioactivity, and on radionuclides in nature (Ch. 2-5). Nuclear radiation emission, absorbance, chemical effects (radiation chemistry), detection and uses is covered in four chapters (Ch. 6-9). This is followed by several chapters on elementary particles, nuclear structure, nuclear reactions and the production of new atoms (radio-nuclides of known elements as well as the transuranium ones) in the laboratory and in cosmos (Ch. 10-17). Before the four final chapters on nuclear energy and its environmental effects (Ch. 19-22), we have inserted a chapter on radiation biology and radiation protection (Ch. 18). Chapter 18 thus ends the fundamental part of radiochemistry; it is essential to all students who want to use radionuclides in scientific research. By this arrangement, the book is subdivided into 3 parts: fundamental radiochemistry, nuclear reactions, and applied nuclear energy. We hope that this shall satisfy teachers with different educational goals.
   The first edition of this book appeared in 1980, and the second edition in 1995. In this third edition we have followed the outline of the second edition. All chapters have been revised, some fundamental ones rather little, but some applied ones more extensively. As the second edition has been scrutinized in years of student courses, we hope that the figures and examples in the text are now as free of errors as it is possible to achieve in a book with extensive numerical information.
   During the years we have received input to our book from researchers, students and teachers from all over the world, both orally and in writing. We have added, corrected or subtracted according to their advice. To make a list of all these contributors would inevitably lead to regrettable omission of some names. To avoid such unfortunate mistakes, we thank everyone who has helped in this way but name none.
   We dedicate our book to the memory of Glenn T. Seaborg (1911-2000) who during his life inspired generations of young scientists to engage in nuclear and radiochemistry to the benefit of mankind. His contributions and his example shall be important for generations to come.

Tallahassee, Florida, and Göteborg, Sweden, July 2001

Gregory Choppin, Jan-Olov Liljenzin, Jan Rydberg

(Updated 2001-10-03)