The objective of this book is to present a comprehensive picture, first of the fundamentals of general contamination of solid surfaces and water, and in the second part, to review the main practical procedures and means of applied decontamination used in the fields of activity. The most emphasis on radioactive contamination deals with decontamination of the operational facilities in nuclear power plants. Other special decontamination branches of current interest are also dealt with briefly. The art of decontamination is being enriched by the progress achieved in relevant scientific disciplines and employs these relative advances. The current volume discusses in detail the following trends in decontamination: Firstly, the development and use of new decontamination methods that are highly efficient, non-aggressive to decontaminated materials, and economically feasible; secondly, the utilization of progressive elements of automation and robotics; thirdly, the development and use of such decontamination formulations that would minimize the volume of wastes and would produce wastes in a form in which they could be either easily further treated or safely disposed of without risk to human health or the environment; finally, the choice of suitable materials used both for the structural and the technological parts of nuclear installations with regard to their minimal contaminability and ease of decontamination.