I only knew of Coffin at the time for his being a defendant in the "Boston 5" trial -- which was held in Boston, and during which I was doing draft counseling. And even then, of course, one only really knew of Dr. Spock, who had been a frequent television presence.
But here and there over the years I've picked up a bit here and there about him. And those bits and pieces are sufficiently inspiring to make me want to know more. (And be reminded of times I saw him, or was in his presence, and didn't know it.) This appears to be a good place to begin that re/discovery.