[Preface to this full issue of Fire Management Today] Mass media images of raging crown fires have affected how many people view their wildlands. Flames surge and leap dozens and even hundreds of feet into the air; planes zoom above the flames releasing streams of brightly colored retardant; and giant pyrocumulonimbus clouds tower over the landscape. No doubt, it's dramatic lead story material. But, to many, and especially those in the wildland fire community, this is serious business. Tens of thousands of acres are severely burned in a single day; homes and lives are endangered; and ecosystems are changed dramatically for decades or longer. Crown fires demand our attention, and they demand serious study. The Joint Fire Science Program is pleased to have contributed to the set of papers appearing in this special volume of Fire Management Today reporting the results of just such a serious study. The Joint Fire Science Program commissioned a thorough synthesis of knowledge and understanding regarding crown fire behavior in coniferous forests a few years ago, and now a summary of the results of that study is presented here in Fire Management Today. We are all indebted to the authors of the papers included in this issue, especially to Dr. Marty Alexander (retired from the Canadian Forest Service and presently an Adjunct Professor at the University of Alberta), who led the project. These summary papers are the culmination of several years of work, and I believe you will find them of great value. Please take a bit of time to give these papers a read. It is good to be armed with the best information available, especially on a serious subject like crown fires.