This volume is intended for the professional who is a newcomer to the area of environmental radon. It marks the first time that chapters on these subjects have been brought together in a single volume, and it is arranged so that anyone with some basic university-level chemistry and physics can develop a clear understanding of the different aspects involved. The volume is intended to serve as a supplementary textbook in public health, environmental, and health physics courses. It also can be used by the professional to get up to speed in this rapidly evolving field. The chapters are not necessarily a discussion of the latest research in this fast-moving field, but are intended to bring the reader to a level at which he can easily understand the current literature. At the back of this volume the reader will find the references for the individual chapters, a general list of reading materials, a glossary, an appendix describing the equations for radioactive decay for a series of progeny, a table of often used conversion factors, and the addresses and brief biographies of the authors and editors. Both historical and SI (International System) units are used throughout the book to provide information for the widest range of readers. Thanks go to Tom Hess for the idea for this volume and to Jessica Barron for help in editing.