The first of two new volumes covering mitochondria, Mitochondrial Function, Part A presents modern methods that have been developed to examine mitochondrial electron transport chain complexes, iron-sulfur proteins and reactive oxygen species. These new techniques provide investigators with sensitive, original approaches to the study of disease states associated with mitochondrial malfunction. The critically acclaimed laboratory standard for 40 years, Methods in Enzymology is one of the most highly respected publications in the field of biochemistry. Since 1955, each volume has been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. With more than 400 volumes published, each Methods in Enzymology volume presents material that is relevant in today's labs -- truly an essential publication for researchers in all fields of life sciences.