This paper is part of a larger project that combines history of economic thought and analytical models to discuss “high development theory”. Here we focus in particular on the contribution of the United Nations ́ Economic Commission for Latin America and the Caribbean (ECLAC, or CEPAL in Spanish). It first briefly examines the historical background of development economics, tracing it back to the seminal contributions of European émigrés to the UK and the US in the 1930s. That highlights the peculiarity of development economics within the progress of economic science and the rise of mainstream economic theory.