"I learned this, at least, by my experiment: that if one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours." So concluded Henry David Thoreau in his 1854 work Walden, a collection of observations made while he lived alone in the woods near Walden Pond for two years in the 1840s. The lessons he learned have since become maxims for living...