La Niña is the result of air-sea interaction and can briefly be described as the appearance of cold surface water in the central and eastern equatorial Pacific Ocean. This volume, based on a meeting of researchers, forecasters, and users of La Niña forecasts, presents updated La Niña Summit papers to introduce the reader to the phenomenon and offers a glimpse of the state of scientific knowledge about cold events and their impacts in developing as well as industrialised societies.