Surplus labour as a source of foreign exchange?

How far can labour-surplus economies, by exporting unskilled workers and/or by importing capital to employ unskilled workers in industries producing for the world market, use their surplus labour as a source of foreign exchange and as a springboard into self-sustaining development? This paper, using the framework of analysis first suggested by Lewis over 25 years ago, emphasizes the danger of expecting too much from such a strategy. Indeed in the gloomy context of the 1980s, with many labour-surplus economies driven towards closing rather than opening, the closed-economy surplus-labour analyses of the 1950s and 1960s may come into their own again.