Over the past 25 years, there have been many advances in the understanding of magnetic phenomena in molecular systems. For example, a variety of low-dimensional materials, and many new ferromagnetic, antiferromagnetic, and ferrimagnetic systems have been synthesized and analyzed; metal cluster compounds that exhibit magnetic exchange have been examined; new orbital overlap theories have been proposed to explain magneto-structural correlations in exchange coupled systems; and efforts directed toward the preparation of an organic ferromagnetic material have produced new and interesting compounds. There have also been many advances in the use of magnetism as a probe of inorganic biomolecules.This volume brings together reviews of current research in magnetochemistry that are written by the world's leading researchers in the fields of chemistry, physics, materials science, and magnetism. It contains comprehensive and in-depth reviews that describe some of the current activities of these scientists and their research and lays the foundation for future research endeavors.