Proceedings of the 13th International Conference on Hyperfine Interactions and 17th International Symposium on Nuclear Quadrupole Interactions, HFI/NQI 2004, held in Bonn, Germany, 22-27 August, 2004.Researchers and graduate students interested in hyperfine interaction detected by nuclear radiation as well as nuclear quadrupole interactions detected by resonance methods in the areas of materials, biological and medical science will find this volume indispensable. New and original scientific results along with recent developments in instrumentation and methods will be communicated in invited and contributed papers.