When I was asked to edit the second edition of Protein NMR Techniques, my first thought was that the time was ripe for a new edition. The past several years have seen a surge in the development of vel methods that are truly revolutionizing our ability to characterize biological macromolecules in terms of speed, accuracy, and size limitations. I was particularly excited at the prospect of making these techniques accessible to all NMR labs and for the opportunity to ask the experts to divulge their hints and tips and to write, practically, about the methods. I commissioned 19 chapters with wide scope for Protein NMR Techniques, and the volume has been organized with numerous themes in mind. Chapters 1 and 2 deal with recombinant protein expression using two organisms, E. coli and P. pastoris, that can produce high yields of isotopically labeled protein at a reasonable cost. Staying with the idea of isotopic labeling, Chapter 3 describes methods for perdeuteration and site-specific protonation and is the first of several chapters in the book that is relevant to studies of higher molecular weight systems. A different, but equally powerful, method that uses molecular biology to edit the spectrum of a large molecule using segmental labeling is presented in Chapter 4. Having successfully produced a high molecular weight target for study, the next logical step is data acquisition. Hence, the final chapter on this theme, Chapter 5, describes TROSY methods for stru- ural studies.