In 1967, the United States Postal Service issued a new five-cent postage stamp to celebrate Henry David Thoreau’s 150th birthday. The stamp proved exceedingly popular, but not for the reasons the USPS might have guessed: The scraggly-bearded portrait of Thoreau by Leonard Baskin became a generational emblem among members of the counterculture, who identified with Thoreau as a tax resistor, abolitionist, and naturalist.