Until very recently, only a handful of Thoreau specialists knew of the existence of The Dispersion of Seeds, an ecological treatise written during the last years of Thoreau’s life, which has been reconstructed and edited, and was published for the first time in 1993. Thoreau’s Late Career and “the Dispersion of Seeds”, the first full-length study of this important late work by Thoreau, analyzes literary features of The Dispersion of Seeds that make it an accomplished work of the imagination, and applies interdisciplinary scholarship in order to relate Thoreau’s prescient ecology to scientific issues of his day and ours. Thus it demonstrates that in his late career Thoreau was working as scientist and poet simultaneously.