In writing this book I had two main objectives: (1) to teach the organic chemist how to interpret proton magnetic resonance spectra, and (2) to provide the reference data which are constantly needed in the use of proton spectra. I have felt that it was im­ portant to point out not only the information which can be gained from spectra, but also the limitations and the potential pitfalls. All of the important facts are organized into tabular summaries. Every effort has been made to present the material clearly, con­ cisely, completely, and accurately. At the same time, subjects not directly related to the interpretation of spectra have been omitted. Thus, while the conclusions drawn from theory are presented, the theory itself has been avoided. There are a number of advantages in learning the empirical facts before learning the theory. First of all, in interpreting spectra one usually has to rely on his knowledge of the accumulated empirical correlations much more than on his knowledge of the theory. In fact, one could know all of the theory and still not b~ able to interpret spectra unless he also knew the empirical facts. Secondly, the theory is much more easilyunderstoodafter the facts have been mastered.