Over the last two decades, mass spectrometry has become one of the central analytical chemistry techniques for indentifying unknown substances and verifying the quality of manufactured substances such as drugs. This book provides a unique approach to understanding how to interpret the spectra produced from a mass spectrometer. Essentially a teach-yourself book, the text is organized in a way that the reader can master the subject by solving real-world problems. Starting from simple questions and building in complexity, the text gradually introduces principles of fragmentation chemistry without going into exhausting detail.