The tree-ring record has become increasingly important to the understanding of the climate system, as topics such as decadal and longer-term patterns attract increasing interest, and it is central to the question of whether current climate changes are extraordinary. It was in this context that 75 scientists from 10 countries met in Tucson, Arizona, last spring to review the current state of dendroclimatology, its contributions since the First International Workshop on Dendroclimatology, in April 1974, and its future potential. The participants included not only those who generate tree-ring records of past climate-dendroclimatologists-but also users of their resultsc climatologists, hydrologists, ecologists, and archeologists.