Introduction to mass spectrometry is the third edition of the introductory book on mass spectrometry (MS) edited by J. Trock Watson. The first edition was published in 1976 and had the subtitle Biomedical, environmental and forensic applications. Its style was quite different from other introductory books on the subject because the first part of the book contained examples of applications of mass spectrometry and was followed by a second part describing the instrumentation and methodology. The examples were very well chosen and illustrative. I liked this concept and, therefore, used the first edition as a textbook in an introductory course in biomedical mass spectrometry until it was outdated by the rapid development of mass spectrometric techniques. The second edition, which I unfortunately do not have available, could not keep abreast of new developments. Now, the third edition has been published. The style has been maintained but the book has more than doubled in size from 239 to 496 pages. This is mainly due to new information being added while much of the earlier information has been retained. Thus, most of the examples on qualitative and quantitative applications of mass spectrometry in Chapters 2 and 3 are the same as those from the first edition. Although the examples are good, they do not show the present wide scope of MS. The use of MS for studies of large biopolymers is only illustrated with one example, which describes the identification of a phosphorylated serine residue in a model peptide by means of MALDI MS.