It has been called the single most historic event of the 20th century On July 20, 1969, after a decade of tests and training, supported by a staff of 400,000 engineers and scientists, and with a budget of billions, the most powerful rocket ever launched brought Neil Armstrong, Buzz Aldrin, and Michael Collins to the moon. Nobody captured the men, the mood, and the machinery like Norman Mailer, hired by LIFE magazine to cover the mission in a dazzling reportage he later enhanced and extended his reportage with deeper reflection in the brilliantly crafted book, "Of a Fire on the Moon", excerpted here for the first time.