Nimoy himself was baffled by the crowds of women who greeted him everywhere he went, so much so that his friend Isaac Asimov tried to explain “Spock-Mania” in a letter: "What really gets the girls is your (or rather, Mr. Spock’s) imperviousness to feminine charm," he wrote. "There is the fascination of trying to break you down that appeals to the hunter instinct of every one of the dear things."