Between 1970 and 1990 - in the space of a generation - primary enrolment increased from 1.5 to 5.5 million, and at secondary level from a little under 150,000 to almost 650,000. No other continent has experienced growth to such a degree within the span of two generations - and this is due in no small measure to the efforts of UNESCO. The rate in higher and post-secondary education has been even faster, but only a minority, under 10 per cent of an age group, is concerned.

And, enrolment has often expanded more quickly than resources, especially teachers and school buildings. At one time or another all countries - and for developed countries especially between the 1950s and the 1970s - have had to take stopgap measures: double-shift systems, pre-fabricated school buildings and recruiting teachers with inadequate training and untrained teaching assistants. Audiovisual media, especially television, were used at first to help teachers with insufficient training and as a prop to the expansion of secondary education in the North and of primary teaching in the South, and subsequently to enhance higher education with the multiplication of open universities and post-graduate distance education.