Appropriate scenarios of future climate must be developed prior to any assessment of the impacts of climate change. The information needed by impact assessors was examined in consultation with those having experience in scenario use. Most assessors require regional scenarios with a temporal resolution of one day and a spatial resolution of around 100 km. Scenarios should contain one or more of: (1) general descriptive statistics of the major climate elements, (2) information about climatic anomalies such as drought, (3) statistics on the frequency and probability of events exceeding particular thresholds, and (4) general synoptic information. Techniques of climate analysis currently available were reviewed for their suitability to meet these scenario needs. The techniques were divided into a series of modules, groups of similar analysis techniques providing a scientifically sound piece of required information. A series of linked modules then provides the complete scenario. One set of modules emphasizes process models, another set uses empirical analyses. The final set involves linkage between the other two. For each module the needs and opportunities for research directed towards scenario development are discussed. (Copyright (c) 1991 American Meteorological Society.)