In excerpts collected here from his most important works, Henry David Thoreau documents his experiences in nature and the wisdom he finds in his explorations of sound, reading, solitude, and other aspects of leading a simple life at Walden. A fearless individualist, Thoreau explored not only poetic naturalism but also a number of ideas that were groundbreaking for his day, including civil disobedience and environmentalism. This introduction to one of America's great thinkers shows that as an essayist and poet-philosopher Thoreau remains a relevant voice in the never-ending quest of man to understand his place in the natural terrain.