This title is the first book to comprehensively address both the experimental and theoretical aspects of this field of research. A leader in the field introduces the basic concepts concerning magnetization and magnetic susceptibility, establishes the fundamental equations of molecular magnetism, and examines molecules containing a unique magnetic center, including the high-spin low-spin transition compounds. The book highlights polymetallic species, reviews the phenomenon of interaction between spin carriers from a theoretical point of view, and includes numerous examples throughout to illustrate the topics discussed.