Mass spectrometry is a modern analytical technique providing fast and ultrasensitive detection and identification of chemical species. This book offers a comprehensive description of mass spectrometry basics, applications, and perspectives. It covers instrumentation, theory, and diverse applications including the analysis of narcotics, counterfeit medicines, components of explosives, clinical chemistry, forensic research, and anti-doping analysis. The text focuses on inorganic, organic, forensic, and biological mass spectrometry methodologies, with special attention to data interpretation techniques. Key terms are provided for newcomers, and test questions assist lecturers. Young researchers will benefit from understanding the power of mass spectrometry alongside complementary methodologies like NMR, pharmacological tests, structural identification, and molecular biology.