Announcing a new volume of Pfleger/Maurer/Weber: Mass Spectral and GC Data of Drugs, Poisons, Pesticides, Pollutants and Their Metabolites. Unmatched in scope, quality and reliability, this collection is the result of a unique effort. Part 4 of this famous reference work contains - 2000 new mass spectra (more than 6300 in Part 1-4) - data of nearly all the new drugs relevant to clinical and forensic toxicology, doping control, food chemistry, etc. - nearly complete coverage of trimethylsilylated, perfluoroacylated, perfluoroalkylated and methylated compounds - data revision of already published volumes in this second edition - updated sections on sample preparation and GC-MS methods - tables covering all the data of Parts 1-4 with directions as to page and volume on/in which the data can be found as well as the appropriate entry numbers of the electronic versions (tables listed by names and categories). The complete set of Part 1-4 now comprises more than 6300 mass spectra and reaches far beyond the needs of clinical and forensic toxicologists. The inclusion of pesticides and pollutants makes this data collection invaluable for environmental chemists, occupational toxicologists and food analysts, too. The data of the supplement volume will also be provided as an up-grade of the computer libraries (PMW_TOX3) by producers of mass spectrometers, e.g., Hewlett Packard, Finnigan (MAT, CE, Automass), Shimadzu and Varian.