Baby Boomers may recall it through a swirl of tear gas, scrawled on walls, on signs in marches and silent sit-ins, or on the helmet covers of weary Vietnam soldiers.
The peace sign, which turns 50 in April, was introduced in a calmer Britain in 1958 to promote nuclear disarmament, and spread fast as times got tense.
Since its inception, it has been revered as a sign of our better angels and cursed as the "footprint of the American chicken."
The symbol that helped define a generation is less evident now, but it is far from forgotten. After what it went through, how could it be?
National Geographic Books is out with "Peace: The Biography of a Symbol," by Ken Kolsbun and Michael Sweeney, which traces the simple symbol from its scratched-out origins based on the semaphore flag positions for N and D (nuclear disarmament) to the influence it had, and retains, in social movements.
While the book details how the symbol came to be and how it spread, it focuses more on the backdrop of the peace movement generally, from its antecedents in the McCarthyism of the 1950s to nuclear proliferation, Vietnam, Kent State and the 1968 Chicago Democratic Convention to its later promotions of other causes.
It has become "a rallying cry for almost any group working for social change," the authors write.
The book is enhanced by numerous photos, some chillingly familiar, some simply nostalgic.
Who can forget the frantic teenager kneeling over the fallen student at Kent State University. Or the student sticking a flower in the barrel of a National Guard rifle? Or the whaling ship bearing down on a Greenpeace raft? Or Woodstock?
The symbol itself was created by a British pacifist textile designer, Gerald Holtom, who initially considered using a cross but got an icy reception from some of the churches he sought as allies.
So on a wet, chilly Good Friday — April 4, 1958 — the symbol as we know it made its debut in London's Trafalgar Square where thousands gathered to support a "ban the bomb" movement and to make a long march to Aldermaston, where atomic weapons research was being done.
While Holtom designed the symbol, the U.S Patent and Trademark Office ruled in 1970 that it is in the public domain. It was quickly commercialized, showing up, among other places, on packages of Lucky Strike cigarettes, but also on a 1999 postage stamp after a public vote to pick 15 commemoratives to honor the 1960s.
Kolsbun is a jack of many trades that include longtime and enthusiastic peace activism, a propensity that shows through. Sweeney is a professor of journalism at Utah State University.
If you recall the mood and times of the '60s and 1970s, the book will take you back. Depending on your level of enthusiasm then, you might imagine a whiff of tear gas. Or recall the better times of the 1967 Summer of Love, which a lot of GIs remember another way.
Holtom clung to his pacifist beliefs to the end, which came on Sept. 18, 1985 at 71. His will requested that his grave marker be carved with two of his peace symbols, inverted.
For reasons unclear, the authors write, they aren't inverted. They're exactly the way he made them.
Maybe that's why.