Chemical analysis moves from laboratory to places where samples to be analysed are located. This trend is aptly termed "on-site analysis". As the dictum says: "from sample transfer to information transfer". Owing to the ever increasing number of samples to be analysed, preliminary screening and selection of samples seems to be necessary, even in the laboratory. Rapid test methods of chemical analysis can solve both these tasks. This book is devoted to test methods that are widely used in environmental, industrial, clinical, forensic, medical, and other areas allowing a rapid, simple and cost-effective analysis - qualitative, semi-quantitative and quantitative to be performed by trained as well as non-trained personnel. Some general characteristic features of test methods and test systems are described in the book, e.g. definitions, advantages and limitations, chemical and physical principles of operation, procedures and protocols, and methodological aspects. Application of test methods in various areas is extensively overviewed, and the test means and test tools pertinent for solving each concrete analytical task are discussed, e.g. paper strips, indicator powders and tubes, tablets, etc. The most important applications of test methods, evidently, are: testing for inorganic and organic components in water (mostly for purposes of environmental control), monitoring of toxic gases and alcohol vapours, detection of narcotics and explosives, determination of glucose, cholesterol, and other components of medical importance.