I'm a complete novice to NMR and this text provides a great introduction to the field with a focus on biological molecules. I've also read parts of Protein NMR Spectroscopy by John Cavanagh and I think Rule's book sets up the stage nicely for the reader to explore further by reading more detailed texts (Cavanagh) on particulars of the field. It's a relatively slim volume and not as intimidating in the mathematical modelling as some of the other books. If you need to understand an NMR phenomenon, read about it in this book first and it'll save you some time in developing an overall picture before looking at pages and pages of derivations in a dusty old book. I have Dr. Rule in part of my classes, I'm a first year grad student, and his amazing teaching ability in the classroom is reflected in the book. Highly recommended to those new to NMR along with Cavanagh's text. I wouldn't leave home without them.