Without neglecting the fundamental theory, this book emphasizes the practical aspects of gas chromatography-mass spectrometry (GC-MS). It discusses important topics such as choosing the most successful device for a given application and the problems usually encountered by novice users and ways to solve them. Additional topics inclu*e acquisition modes in GC-MS, quadrupolar analyzer performance, quantification by GC-MS, spectra databases for GC-MS, dissociation mechanisms, and mass spectra interpretation. The book supports theoretical demonstrations with numerous examples and figures to assist with reader assimilation.