The availability of the photosynthetic reaction center's structure at an atomic resolution of less than three angstroms has revolutionized research. This protein is the first integral membrane protein whose structure has been determined with such precision. Each volume of the Photosynthetic Reaction Center contains original research, methods, and reviews. Together, these volumes cover our current understanding of how photosynthesis converts light energy into stored chemical energy. Volume I describes the chemistry and biochemistry of photosynthesis, including green plant photosynthesis; it is devoted to the overall features and implications of the bacterial reaction center for green plant research. It features a new description of the structure of the reaction center, followed by coverage of the antenna and light functions. Volume I also details new manipulations of the reaction center including chemical and genetic modifications. It describes how the reaction center provides reducing power via electron transfer chemistry coupled to proton uptake and release; coupling of electron transport between the oxidized reaction center and the aqueous periplasm; and the general operation of membrane-bound proteins. Additionally, this volume contains five chapters detailing facets of green plant photosynthesis important for future research.