We are proud to present Volume 3 of Biological Magnetic Resonance, a series that has met with praise from the scientific community. This volume covers the new applications of various multiple irradia- tion techniques to the NMR of biomolecules; the chapter of Keller and Wuthrich describes much of the technique and its applications to hemo- proteins. The ESR of some hemoproteins in the single crystal is described by Chien and Dickinson, who also include...