Introduction: Ultrafast Reactions in Photosynthesis

The present issue of Photochemistry and Photobiology deals with the “ultra‐fast reactions” in the primary process of photosynthesis. The definition of what one calls “ultra‐fast reactions” was left to the individual authors; it ranged from picoseconds (ps) to microseconds ( μ s). All of the papers were invited for this issue; these include those presented by the various speakers (to be cited at appropriate places) at the symposium on “ Primary Photoprocesses in Photosynthesis: Ultrafast Reactions ” held at the 5th annual meeting of the American Society for Photobiology, May 11–15, 1977, in San Juan, Puerto Rico. All the papers in this issue were reviewed by three authorities in the field, and the authors have incorporated as many of their suggestions as possible. I thank all the reviewers for their help and their names will be included in the annual list of the reviewers of the entire journal of Photochemistry and Photobiology.