Every spring for as long as some folks in east-central Kansas can recall, ranchers--like Native Americans before them--set fire to vast areas of tall-grass prairie as a way of returning nutrients to the soil and encouraging new growth. For more than a decade, photographer Larry Schwarm, a professor at Emporia State University in Kansas, has documented this annual ritual. His efforts are collected in a 128-page book, On Fire, published by Duke University Press, in association with Lyndhurst Books of the Center for Documentary Studies.