This was the second time demographers from all over the world had been brought together under the joint auspices of the United Nations and the International Union for the Scientific Study of Population. The first was in Rome, in 1954. The progress made over this decade is indeed tremendous. To begin with, the difference is one of sheer dimension: at the Belgrade conference more than oo papers were presented, including a large number of extremely valuable background papers, and the number of participants was around 800.