The International Crown Fire Modelling Experiment (ICFME) constitutes a major, cooperative, global undertaking involving coordination by the Canadian Forest Service Fire Research Network (CFS-FRN) and the Government of the Northwest Territories' Forest Management Division combined with participation of collaborating scientists and operational fire personnel, principally from Canada and the USA, but with representation from several other countries as well. The initial impetus for the ICFME was oriented towards the testing and calibration of a newly developed physical model for predicting the spread rate and flame front intensity of crown fires. However, the ICFME has also provided the opportunity to examine other aspects or implications of crown fire behavior, without compromising this primary objective, including linkages to fire-fighter safety/personal protective equipment (PPE) and wildland-urban interface or intermix issues as well as certain ecological and environmental impacts or effects, including concerns about atmospheric chemistry from biomass burning. The 11 experimental crown fires that have taken place in the last three years (1997-99) are providing valuable new data and insights into the nature and characteristics of crowning forest fires needed for dealing with the management problems and opportunities that will be affecting both people and ecosystems in the coming century.