Animal, plant, and microbial ecophysiologists have diverged greatly in the last few decades in the principal research questions they address (e.g., global change versus evolution), in the methods they use, and even in the professional societies to which they belong. Two symposia in 2001 brought these diverse groups together, with presentations by researchers who study two or three kingdoms in intimate interaction. The second symposium, the subject of this report, was sponsored by the Ecological Society of America's Physiological Ecology section. Several of the presentations showed, among other things, commonalities in chemical signaling among kingdoms, as well as exploitation of such signals and other metabolic pathways by parasites and their hosts. These and other important findings from such interkingdom and interdisciplinary research can help explain why current functional groups exist.